Method for applying a water-based road marking paint and a curing accelerator for water-based paints

Abstract

To provide a coating method of a water-based road surface marking paint using a curing accelerator which reduces the time required for traffic blockages and regulations during marking work by accelerating post-application curing of the water-based road surface marking paint, of which a minimum amount necessary is used to cure a coating film of the water-based road surface marking paint, and which scatters little.SOLUTION: In a coating method in which a water-based road surface marking paint containing synthetic resin emulsion as a main component is applied to a road surface, and a curing accelerator is brought into contact with the applied water-based road surface marking paint, the curing accelerator is an aqueous solution whose viscosity is adjusted with a water-soluble metal salt and a viscosity modifying agent, and its viscosity is lower than that of water-based road surface marking paint and is in the range of 10 mPa s or more, so that the curing accelerator accelerates the curing of the road surface marking paint after application, reducing the time required for traffic blockages and restrictions during marking work, and a minimum amount necessary of it is used for curing the coating film of water-based road surface marking paint, and it scatters little.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a coating method using a curing accelerator when applying an aqueous road marking paint for marking on a road surface, and further relates to a curing accelerator for aqueous paints.

Background Art

[0002] On roads and the like, markings such as traffic signs such as lane dividing lines and stop lines, and crosswalk signs are marked, and appropriate information is marked for vehicle drivers and pedestrians by such markings. These markings are marked by using a road marking paint and applying it to a road or the like to form a coating film.

[0003] This road marking paint is increasingly being an aqueous road marking paint that takes environmental considerations. Unlike the conventionally used organic solvent-based road marking paint, this aqueous road marking paint forms a coating film by evaporation of water as a dispersion medium. However, in this aqueous road marking paint, water as a dispersion medium does not evaporate as quickly as an organic solvent, and the curing time until a coating film is formed tends to be long, and it often takes a long time for the construction for the marking.

[0004] When this construction is carried out, it is necessary to carry out long-time traffic interruption and regulation until the aqueous road marking paint is applied and cured. Therefore, a coating method for an aqueous paint as disclosed in Patent Document 1 has been proposed.

[0005] This coating method for an aqueous paint is a coating method in which, when applying an aqueous emulsion paint having an emulsion polymer as a coating film forming element to a road surface, a curing accelerator is brought into contact with the aqueous paint, and the curing accelerator is a water-soluble acid and a water-soluble metal salt, either separately or mixed. Thereby, the curing time of the coating film after applying the aqueous paint can be significantly shortened, and the time for traffic interruption and regulation in the construction for marking can be shortened.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when this curing accelerator is brought into contact with an aqueous paint, the curing accelerator is often sprayed and brought into contact with the aqueous paint, and in this case, the curing accelerator often scatters, so that the curing accelerator is consumed in an amount more than necessary for the curing of the aqueous paint. In addition, the scattered curing accelerator may promote rusting of tools required for the work and adjacent iron members.

[0008] The present disclosure promotes the curing after application of an aqueous road marking paint, shortens the time for traffic interruption and regulation in marking work, etc., and provides a method for applying an aqueous road marking paint with a curing accelerator that has a small amount of scattering and the minimum amount necessary for curing the coating film of the aqueous road marking paint.

Means for Solving the Problems

[0009] In a coating method in which an aqueous road marking paint mainly composed of a synthetic resin emulsion is applied onto a road surface and a curing accelerator is brought into contact with the applied aqueous road marking paint, the curing accelerator is an aqueous solution whose viscosity is adjusted by a water-soluble metal salt and a viscosity modifier, and the viscosity is lower than that of the aqueous road marking paint and is in the range of 10 mPa·s or more. Thereby, the curing after application of the road marking paint is promoted, the time for traffic interruption and regulation in the work for marking is shortened, and a curing accelerator with less scattering and the minimum amount necessary for curing the coating film of the aqueous road marking paint is obtained.

[0010] The aqueous road marking paint contains an anionic synthetic resin emulsion containing a carboxyl group, an amine functional group-containing polymer, and a volatile base, and the curing accelerator contains a water-soluble acid. This enables the use of a curing accelerator with minimal scattering at the minimum required amount for curing the coating film of the aqueous road marking paint, which further promotes the curing after the application of the road marking paint, and makes it possible to shorten the time for traffic interruption and regulation in the marking work.

[0011] The water-soluble metal salt contained in the curing accelerator is a divalent metal salt, the water-soluble acid is a carboxylic acid, and the combined concentration of the water-soluble metal salt and the water-soluble acid is in the range of 10.0 to 45.0% by weight. This enables the use of a curing accelerator with minimal scattering at the minimum required amount for curing the coating film of the aqueous road marking paint, which further promotes the curing after the application of the road marking paint.

[0012] When the viscosity adjusted by the water-soluble metal salt and the viscosity modifier is in the range of 10 to 50 mPa·s, it is a curing accelerator with minimal scattering at the minimum required amount for curing the coating film of the aqueous paint, which promotes the curing after the application of the aqueous paint.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0014] Embodiments of the present disclosure will be described. The present disclosure relates to a coating method in which an aqueous road marking paint mainly composed of a synthetic resin emulsion is applied onto a road surface, and a curing accelerator is brought into contact with the applied aqueous road marking paint. The curing accelerator is an aqueous solution whose viscosity is adjusted by a water-soluble metal salt and a viscosity modifier, and the viscosity is lower than that of the aqueous road marking paint and is in the range of 10 mPa·s or more.

[0015] First, this aqueous road marking paint is the one specified in JIS K 5665 and is of the aqueous type. This aqueous road marking paint is often used because it is easy to handle and the like. This paint for aqueous road marking may use a synthetic resin emulsion produced by a common polymerization technique such as emulsion polymerization as its binder. Also, even if the structure of the polymer of the synthetic resin emulsion is in a complex form, for example, core-shell particles, it can be implemented.

[0016] This aqueous road marking paint, in addition to the synthetic resin emulsion, contains coloring components such as white pigments such as titanium oxide, kaolin, talc, and clay, inorganic pigments such as iron oxide, and coloring pigments such as organic pigments, and is colored. Also, it often contains extender pigments such as calcium carbonate, diatomaceous earth, aluminum hydroxide, bentonite, white carbon, precipitated barium, and silica sand, and fibers.

[0017] Also, components generally incorporated in paint production, such as dispersants, wetting agents, surfactants used as defoaming agents, thickeners, leveling agents, viscosity modifiers such as anti-sagging agents, organic solvents used as low-boiling alcohols, film-forming aids, and antifreezing agents, can also be used. Also, additives such as pH adjusters, preservatives, fungicides, algicides, and waxes may be added as necessary.

[0018] The curing accelerator is an aqueous solution whose viscosity is adjusted by a water-soluble metal salt and a viscosity modifier, and the viscosity is lower than that of the aqueous road marking paint and is in the range of 10 mPa·s or more. This viscosity refers to the viscosity at 60 revolutions of a B-type viscometer at 23°C. This water-soluble metal salt refers to a metal salt that dissolves 10 g or more in 100 g of water at 20°C, and is not particularly limited.

[0019] This water-soluble metal salt can aggregate the synthetic resin emulsion by contacting the synthetic resin emulsion of the aqueous road marking paint, making the applied aqueous road marking paint unstable, quickly gelling, immobilizing the fluid road marking paint, and promoting curing. This water-soluble metal salt only needs to have a solubility in water of 10 g / 100 g (20°C) or more, and those that dissolve more are preferred, which makes it easier to prepare the curing accelerator.

[0020] Regarding this water-soluble metal salt, as will be described later, many of them promote the rusting of iron. Therefore, the curing accelerator needs to be adjusted so that there is less scattering to the surroundings. The viscosity modifier can be the same as those used in the aqueous road marking paint. The type and addition amount of the viscosity modifier used are set according to the type of the water-soluble metal salt, the concentration of the curing accelerator, and the set viscosity to obtain the desired viscosity and stickiness, and to give a certain viscosity and thixotropy to the curing accelerator.

[0021] This viscosity modifier can increase the viscosity of the curing accelerator and impart stickiness because the molecules are long and it exists in a swollen form in water when dissolved in water. Its forms include powdery and liquid ones. This curing accelerator is made sticky by the viscosity modifier described above. When the curing accelerator is brought into contact with the aqueous road marking paint in a thixotropic state, especially when applied and contacted by spraying, the scattering is less, so that only the minimum amount necessary for the curing of the coating film is required. The viscosity of this curing accelerator only needs to be 10 mPa·s or more. If it is lower than this, the scattering amount of the curing accelerator will increase, and the scattered curing accelerator may adhere to the tools required for the construction and the adjacent iron members, etc., causing rusting.

[0022] Also, it is necessary that the viscosity be lower than that of the aqueous road marking paint targeted by the curing accelerator. If it is higher than this, the spray width of the aqueous road marking paint will become narrower, and it will not be possible to sufficiently accelerate the curing of the entire painted surface. The upper limit value of the viscosity of this curing accelerator may be 7000 mPa·s or less. If it is below this viscosity, it can be uniformly applied to the application surface of the aqueous paint, and it is possible to sufficiently accelerate the curing of the entire painted surface.

[0023] By giving the curing accelerator a viscosity in this way and having a certain degree of viscosity and thixotropy, it will be less likely to scatter with the minimum amount required for the curing of the coating film of the aqueous road marking paint. Especially when the curing accelerator is applied by spray coating, its characteristics will be fully exhibited. The application amount of the aqueous road marking paint depends on conditions such as the road surface condition, the type of paint, and the construction specifications, but it is often appropriately selected from the range of 100 to 3000 g / m 2 of.

[0024] The application amount of the curing accelerator varies depending on the type of the aqueous road marking paint, but it is often appropriately set from the range of 1.0 to 30.0 g of the curing accelerator per 100 g of the paint. If it is less than this range, it may be difficult to obtain a sufficient effect of accelerating the curing of the coating film. If it is more, the effect of the extra application may not be obtained. If it is within this range, a sufficient effect of accelerating the curing can be obtained.

[0025] Next, the coating method of bringing the above-described aqueous road marking paint and the curing accelerator into contact will be specifically described. As the coating method of bringing the aqueous road marking paint and the curing accelerator into contact, there is a coating method of bringing them into contact as shown in FIGS. 1 and 2.

[0026] This coating method often uses a marker vehicle with a spray gun such as an air spray gun or an airless spray gun mounted on an automobile or a pushcart. This marker vehicle is loaded with two types of spray guns, namely, a spray gun 11 for aqueous road marking paint and a spray gun 15 for a curing accelerator, and the operation is carried out in this way. Regarding the application of the aqueous road marking paint, it is also possible to apply it with a brush or a painting roller. After applying the aqueous road marking paint, a curing accelerator is applied with a spray gun.

[0027] This is because if the curing accelerator is included in a brush or a painting roller and brought into contact with the aqueous road marking paint, the aqueous road marking paint may adhere to the brush or the painting roller, and marking may not be possible. In this application, in order to improve the night visibility of the marking, glass beads may be sprayed simultaneously with the painting on the paint surface or in the paint, and this is preferably carried out. The spraying of these glass beads will be described.

[0028] These glass beads include those with a large spherical particle size of about 500 to 1700 μm in particle diameter and those with a small particle size of about 106 to 850 μm in particle diameter. Their refractive index is about 1.5 to 2.5, which causes retroreflection when light hits them, and is for improving the night visibility of the marking and the like. The spray gun 11 for aqueous road marking paint and the spray gun 15 for a curing accelerator may be of the airless spray type or the air spray type. The glass bead spreader 14 was of the natural fall type.

[0029] In FIG. 1, with respect to the road surface R, a paint layer 12 is formed by applying with the spray gun 11 for aqueous road marking paint. At the same time, glass beads 13 are sprayed on the paint layer 12 with a bead spreader 14, and a curing accelerator is sprayed onto the paint layer 12 by spraying with the spray gun 15 for a curing accelerator, so that the curing accelerator is brought into interfacial contact with the aqueous road marking paint.

[0030] By adding viscosity to the curing accelerator and using a viscous one, when applying the aqueous road marking paint and then applying the curing accelerator, the uncured paint layer 12 will be coated with the viscous curing accelerator, thus protecting the paint layer 12. This can protect the paint layer 12 from external factors such as a little rain.

[0031] In Fig. 2, in the method of Fig. 1, the curing accelerator is sprayed with a spray gun 15 for the curing accelerator toward the same position as when applying the aqueous road marking paint, and the paint layer 12 is formed while the curing accelerator is mixed and contacted with the aqueous road marking paint. Contact the aqueous road marking paint with the curing accelerator as shown in Figs. 1 and 2. The aqueous road marking paint contacted by this curing accelerator starts to aggregate the synthetic resin emulsion and forms a stable, immobilized, non-fluid coating film. This coating film, the paint layer 12, evaporates moisture and the paint components are concentrated and aggregated.

[0032] Then, the particles of the synthetic resin emulsion in the paint components fuse with other particles to form a cured coating film. This promotes the curing after the application of the aqueous road marking paint, shortens the time for traffic interruption and regulation in the marking work, and is due to the curing accelerator with little scattering with the minimum amount required for the curing of the coating film of the aqueous road marking paint.

[0033] Also, this uncured coating film will not flow even in the case of rainfall immediately after painting, low temperature, or rainfall at low temperature, and then gradually forms a cured coating film. Generally, construction of this aqueous road marking paint is not carried out at 5°C or lower. The reason is that a cured coating film cannot be obtained after applying the aqueous road marking paint, and the uncured coating film will flow due to rainfall or the like.

[0034] However, according to the coating method of the present disclosure, the construction of the aqueous road marking paint can be carried out even without obtaining a cured coating film in a low temperature state such as 5°C or lower. Furthermore, the water-based road marking paint and the curing accelerator, which are the constituent elements of the present disclosure, will be described in more detail.

[0035] As the synthetic resin emulsion described above, a general one obtained by homopolymerizing or copolymerizing resins such as acrylic resin, urethane resin, vinyl chloride resin, silicone resin, vinyl acetate resin, polyester resin, styrene resin, and fluororesin is used. Among these, from the viewpoints of paint suitability, physical properties of the coating film, ease of availability, etc., acrylic-based synthetic resin emulsions and acrylic styrene-based synthetic resin emulsions produced from acrylic resin and styrene resin are often used.

[0036] The glass transition temperature of the resin used in this synthetic resin emulsion is preferably in the range of -50 to 70 °C, and a synthetic resin with a suitable glass transition temperature can be selected as needed. The above synthetic resin emulsion is an anionic synthetic resin emulsion containing a carboxyl group, and at the same time, it is preferable to contain an amine-functional group-containing polymer and a volatile base in the water-based road marking paint.

[0037] By using a synthetic resin emulsion having such a configuration, the curing of the water-based road marking paint is accelerated, and the use of a curing accelerator can further accelerate the curing. This anionic synthetic resin emulsion containing a carboxyl group and containing an amine-functional group-containing polymer and a volatile base is in a stable state as a paint in an alkaline state.

[0038] However, when the volatile base volatilizes and the paint becomes neutral, the synthetic resin emulsion becomes unstable, starts to aggregate, and turns into a gelled state where the paint loses its fluidity. That is, after such a water-based road marking paint is applied, the volatile base evaporates, the paint changes to acidic, and a non-cured coating film without fluidity that has gelled is formed, and a cross-linking reaction occurs between the carboxyl group of the synthetic resin emulsion and the amine functional group of the amine-functional group-containing polymer.

[0039] Then, the moisture in the coating film evaporates, the aqueous paint components are concentrated and aggregated, and the particles of the synthetic resin emulsion fuse while entrapping other particles to form a cured coating film. This carboxyl group undergoes a crosslinking reaction with the amine functional group of the amine functional group-containing polymer, gelling the aqueous road marking paint to form a coating film. Thereby, the strength and weather resistance of the formed and cured coating film can be improved.

[0040] The amine functional group-containing polymer has an amine functional group contained in the amine functional group-containing polymer as a constituent element, and thus undergoes a crosslinking reaction with the carboxyl group contained in the synthetic resin emulsion to form a coating film. This amine functional group-containing polymer is a polymer formed from a monomer mixture containing one or more amine functional group-containing monomers among primary amines, secondary amines, and tertiary amines, and can be obtained by solution polymerization in a neutral, alkaline, or acidic aqueous medium depending on the polymer.

[0041] Due to its miscibility with the synthetic resin emulsion, a water-soluble or water-dispersible polymer is preferably used as this amine functional group-containing polymer. The volatile base stabilizes the aqueous road marking paint in the range of pH 7.0 to pH 10.0, whereby the amine functional group of the amine functional group-containing polymer contained in the aqueous road marking paint is in a nonionic or anionic state, and it can be stored stably.

[0042] After the application of the aqueous road marking paint, the volatile component of this volatile base starts to evaporate, lowering the pH of the paint until the conversion of the amine functional group in the nonionic or anionic state to the cationic state starts to occur. In that state, the amine functional group becomes cationic, and the gelling of the aqueous road marking paint starts. This gelling is initiated by the conversion of the amine functional group to the cationic state.

[0043] Suitable volatile bases include ammonia, methylamine, ethylamine, propylamine, isopropylamine, dimethylamine, trimethylamine, etc. Ammonia, which has a low boiling point of -33.4°C and rapid evaporation, or those with ammonia as the main component, are preferably used. In addition, an alkali-providing agent that is liquid or solid at normal temperature may be added. This alkali-providing agent may use a pH adjuster commonly used in paint formulations to stabilize the aqueous road marking paint in a nonionic or anionic state together with the volatile base.

[0044] Examples of the alkali-providing agent that is liquid or solid at normal temperature include amines and alkali metal salts. Examples of amines include morpholine, 2-dimethylaminoethanol, N-methylmorpholine, ethylenediamine, and 2-amino-2-methyl-1-propanol, etc. Examples of alkali metal salts include sodium hydroxide and potassium hydroxide.

[0045] Suitable water-soluble metal salts described above include calcium chloride, magnesium chloride, iron dichloride, zinc chloride, sodium chloride, barium chloride, nickel chloride, magnesium nitrate, magnesium sulfate, manganese dichloride, etc., and can be preferably used. These water-soluble metal salts can be used singly or in combination of two or more, and are selected and used as needed.

[0046] Among these, divalent metal salts are preferably used. In particular, calcium chloride and magnesium chloride are more preferably used because of their excellent stability and low cost. Also, when adjusting the curing accelerator, it is desirable to use a combination of those that generate heat and those that absorb heat.

[0047] For example, when calcium chloride is mixed with water, heat is generated, and there may be a rapid temperature rise during the preparation. By adding magnesium chloride, which absorbs heat, during this preparation, the balance between heat generation and heat absorption can be achieved, making these preparations easier. This divalent metal salt can aggregate the synthetic resin emulsion in a relatively small amount, form an uncured coating film in a non-fluid state with the aqueous road marking paint stably immobilized, and can further promote curing.

[0048] Since marking work may be carried out in winter or cold regions, etc., the concentration of this aqueous metal salt is preferably about a concentration at which no precipitate precipitates even below the freezing point. Although it varies depending on its type, it is more preferably about 90% by weight or less of the saturation concentration at normal temperature (20 - 25°C). Also, the concentration is preferably 10% by weight or more. If it is lower than this, it may not be possible to promote the curing of the aqueous road marking paint, which is one of the effects of the curing accelerator. Further, it is more preferably 20% by weight or more. At this concentration, it is possible to expect promotion of curing at low temperatures such as 5°C.

[0049] As the viscosity regulator described above, those similar to those generally used in paint formulations can be used. However, depending on the type of water-soluble metal salt and the type of water-soluble acid described later, there are some that are difficult to increase in viscosity, so prior confirmation may be required in some cases. Also, the addition amount of the viscosity regulator for obtaining the desired viscosity of the curing accelerator also requires prior confirmation.

[0050] This viscosity modifier includes cellulose derivative compounds such as methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and hydroxypropyl cellulose; inorganic compounds such as water-soluble alkali silicate, montmorillonite, and colloidal alumina; polyether compounds such as polyether dialkyl ester, polyether dialkyl ether, polyether urethane-modified product, and polyether epoxy-modified product; polyacrylic acid compounds such as sodium polyacrylate and poly(acrylic acid / (meth)acrylic acid ester) copolymer; polyvinyl compounds such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl benzyl alcohol copolymer; protein derivatives such as sodium caseinate and ammonium caseinate; partial esters of vinyl methyl ether-maleic anhydride copolymer, allyl alcohol ester of drying oil fatty acid-maleic anhydride copolymer, alkali-swellable viscosity modifiers, and urethane association-type viscosity modifiers. They can be used alone or in combination of two or more.

[0051] In addition, when the synthetic resin emulsion is an anionic synthetic resin emulsion containing a carboxyl group and the aqueous road marking paint contains an amine-functional group-containing polymer and a volatile base, by including a water-soluble acid in the curing accelerator, the curing of the aqueous road marking paint becomes faster. By adding a water-soluble acid to an aqueous road marking paint that is an anionic synthetic resin emulsion containing a carboxyl group and contains an amine-functional group-containing polymer and a volatile base, and bringing it into contact with an acidic curing accelerator, the aqueous road marking paint quickly becomes acidic and gelation is promoted.

[0052] This water-soluble acid includes organic acids and inorganic acids. Examples of organic acids include carboxylic acids such as citric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and acetic acid. Examples of inorganic acids include hydrochloric acid, sulfuric acid, and phosphoric acid. Among them, those of organic acids are preferred due to ease of handling, and citric acid, which is a polycarboxylic acid, is more preferred. Many polycarboxylic acids have a small acid dissociation constant pKa, and a small amount makes the acidity strong, and faster curing acceleration can be expected.

[0053] When the aqueous road marking paint contains an anionic synthetic resin emulsion containing a carboxyl group, an amine functional group-containing polymer, and a volatile base, and a water-soluble acid is contained in the curing accelerator, the aqueous road marking paint and the curing accelerator come into contact, and the volatile base in the paint evaporates, and the pH of the paint rapidly decreases due to the water-soluble acid of the curing accelerator.

[0054] The amine functional group in the aqueous road marking paint that is stable in the nonionic or anionic state becomes cationic when the pH drops to the point where the conversion of the amine functional group to the cationic state begins. This cationic amine functional group is electrically attracted to the anionic synthetic resin and gels. At the same time, the aggregation of the synthetic resin emulsion begins due to the water-soluble metal salt of the curing accelerator, gels, and forms an uncured paint film in a stable and immobilized state without fluidity.

[0055] Furthermore, in this uncured paint film, the distance between the polymers of the amine functional group-containing polymer and the anionic synthetic resin emulsion becomes closer. The carboxyl group of the polymer of the anionic synthetic resin and the amine functional group of the amine functional group-containing polymer containing the cationic amine functional group are ionically bonded to initiate a crosslinking reaction.

[0056] Then, in this uncured paint film, water evaporates, the paint components are concentrated and aggregated, and the particles of the synthetic resin emulsion in the paint components fuse with other particles to form a cured paint film. Thereby, with the minimum required amount for curing the paint film of the aqueous road marking paint, a curing accelerator with less scattering can further promote the curing after the application of the aqueous road marking paint, and can shorten the time for traffic interruption and regulation in the marking work.

[0057] This water-soluble acid is preferably one that dissolves more. Its concentration is preferably adjusted to a level such that no precipitate precipitates even below the freezing point because marking work may be carried out in winter or cold regions. Although it varies depending on the type of the water-soluble acid, it is generally more preferable to be about 90% by weight or less of the saturation concentration at normal temperature (20 to 25 °C).

[0058] Moreover, the concentration is preferably 5% by weight or more. When it is lower than this, the promotion of the curing of the water-based road marking paint, which is one of the effects of the curing accelerator, may be insufficient. When the amount of water in the curing accelerator becomes excessive, it may also inhibit the gelation of the water-based road marking paint. In addition, the combined concentration of the water-soluble metal salt and the water-soluble acid is preferably 15% by weight or more. At this concentration, the promotion of curing at low temperatures such as 5 °C can be expected.

[0059] The ratio of the water-soluble metal salt to the water-soluble acid is preferably in the range of 3:1 to 1:1 by weight. Within this range, a well-balanced curing promotion can be obtained. The application method of the water-based road marking paint configured as described above will be described in detail with specific examples.

[0060] First, the asphalt stones, dust, garbage, etc. on the road surface where the water-based road marking paint is to be applied were removed as much as possible, and marks were made on the parts to be marked. This operation was carried out in a parking lot paved with asphalt. In addition to such parking lots, the road surfaces to which this water-based road marking paint is applied include roads, passageways, etc. paved with asphalt or concrete, and those including floor surfaces indoors such as warehouses and parking lots.

[0061] Here, two types of water-based road marking paints were used for comparison. The first type of water-based road marking paint (1) used an acrylic resin-based synthetic resin emulsion in JIS K 5665, and titanium oxide as a white pigment, calcium carbonate as a extender pigment, surfactants as a dispersant, a wetting agent, an antifoaming agent, and a viscosity modifier were added. Its viscosity was 5000 mPa·s.

[0062] For the two types of aqueous road marking paints (2), Keys Liner manufactured by Kikusui Chemical Industry Co., Ltd. was used. This Keys Liner uses an anionic acrylic resin-based synthetic resin emulsion containing a carboxyl group in the synthetic resin emulsion, and contains an amine functional group-containing polymer and a volatile base in the paint. Its viscosity was also 5000 mPa·s.

[0063] Two types of curing accelerators were also used and compared. The first type of curing accelerator (a) is an aqueous solution in which calcium chloride and magnesium chloride are mixed in a ratio of 1:1 in water, and the concentration of the combined water-soluble metal salt is 30.0%, and its viscosity was adjusted to 35 mPa·s with a viscosity modifier. The second type of curing accelerator (i) is a mixture of the curing accelerator (a) and citric acid. The ratio of the water-soluble metal salt (calcium chloride and magnesium chloride) to the water-soluble acid (citric acid) is 3:1, and its concentration was adjusted by the amount of water to be 30.0%, and its viscosity was 35 mPa·s.

[0064] These coatings were applied using a hand marker vehicle with the coating device shown in Fig. 1 loaded on a handcart. The ratio of contacting the curing accelerators (a)(i) with the aqueous road marking paints (1)(2) was verified in advance to ensure an appropriate curing time, and the setting was made to be 7 g with respect to 100 g of the aqueous road marking paint.

[0065] Also, the scattering state of the curing accelerator during spray coating was compared between the state before adding the viscosity modifier of the curing accelerator (a) and the state after adding it (curing accelerator (a)). In the situation of that coating, the curing accelerator (a) with the viscosity modifier added had significantly less scattering, and the adjustment of the spray coating width could be easily controlled.

[0066] Also, when the application amount of the curing accelerator was 20 g, the amount of the curing accelerator used was 21 g for the curing accelerator (a), but it was 25 g for those without adding the viscosity modifier. From these results, it was confirmed that by adding a viscosity modifier, the amount of the curing accelerator scattered was significantly reduced.

[0067] Before applying to the road surface, the application amount of each was set. The average application amount of the aqueous road marking paints (1) and (2) was set to an amount that would be 200 g / m 2 and the application width was set to 150 mm. The average application amount of the curing accelerators (A) and (B) was set to an amount that would be 17 g / m 2 and the application width was set to 160 mm, which is wider than 150 mm.

[0068] The curing rates of these aqueous road marking paints (1) and (2) and the curing accelerators (A) and (B) were verified by combining them. The combinations are shown below. A. Only the aqueous road marking paint (1) B. Only the aqueous road marking paint (2) C. Aqueous road marking paint (1) and curing accelerator (A) D. Aqueous road marking paint (2) and curing accelerator (A) E. Aqueous road marking paint (2) and curing accelerator (B)

[0069] This application was carried out for 5 m for each combination, and the curing rate was measured over time. The air temperature during the application was 7°C. This curing refers to the state where the applied aqueous road marking paint has lost its fluidity and the paint has aggregated and cured to form a film. The determination was based on the touch-dryness specified in JIS K 5600-1-1.

[0070] The temperatures of these aqueous road marking paints and the curing accelerators were the same as the air temperature, 7°C. Both of the two curing accelerators had the same consistency as those stored at room temperature without precipitates. The application work was carried out using a hand marker vehicle loaded with an application device having the configuration shown in Fig. 1.

[0071] The curing times were 20 minutes for A, 15 minutes for B, 13 minutes for C, 13 minutes for D, and 11 minutes for E. From these results, the effect of the curing accelerator could be confirmed.

Explanation of symbols

[0072] 11 Paint spray gun 12 Paint layer (fluid coating film) 13 Glass beads 14 Bead spreader machine 15 Accelerator spray gun R Road surface

Claims

1. In a coating method of applying an aqueous road marking paint containing a synthetic resin emulsion as a main component onto a road surface and bringing a curing accelerator into contact with the applied aqueous road marking paint, The coating method of the aqueous road marking paint, wherein the curing accelerator is an aqueous solution whose viscosity is adjusted by a water-soluble metal salt and a viscosity modifier, the viscosity of which is lower than that of the aqueous road marking paint and is in the range of 10 mPa·s or more.

2. The aqueous road marking paint contains an anionic synthetic resin emulsion containing a carboxyl group, an amine-functional group-containing polymer, and a volatile base, The coating method of the aqueous road marking paint according to claim 1, wherein the curing accelerator contains a water-soluble acid.

3. The water-soluble metal salt contained in the curing accelerator is a divalent metal salt, The water-soluble acid is a carboxylic acid, The coating method of the aqueous road marking paint according to claim 1 or claim 2, wherein the combined concentration of the water-soluble metal salt and the water-soluble acid is in the range of 10.0 to 45.0% by weight.

4. A curing accelerator for an aqueous paint, the viscosity of which is adjusted by a water-soluble metal salt and a viscosity modifier and is in the range of 10 to 7000 mPa·s.

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