JP2021038584A - Coating film forming method - Google Patents

Abstract

To provide a coating film forming method capable of suppressing deterioration of an existing coating film and keeping beauty for a long period of time, while utilizing an uneven pattern and a color pattern of an existing wall face.SOLUTION: A coating film forming method of this invention coats a coating material to an age-deteriorated existing wall face. The existing wall face has an uneven pattern on a surface and comprises an existing coating film. The coating material includes a non-aqueous solvent (A), a resin component (B), and a thickener (C). The resin component (B) includes a polyol compound and a polyisocyanate compound, and includes an acrylpolyol compound with 40000 or lower of weight average molecular weight as the polyol compound. The coating material forms a coating film having a visible light transmission property, and ultraviolet transmittance is 30% or less.SELECTED DRAWING: None

Description

The present invention relates to a film forming method applicable to buildings and the like.

Conventionally, on the wall surface of the exterior of a building, various coating materials are formed on various base materials for the purpose of protecting the base materials and improving the aesthetic appearance. From the viewpoint of aesthetics and the like, such a wall surface is often provided with an uneven pattern or a color pattern. However, since such a wall surface (existing wall surface) is exposed outdoors for a long period of time, deterioration progresses due to the influence of sunlight, precipitation, etc., and the initial aesthetic appearance deteriorates over time.

On the other hand, in recent years, there has been a movement to repaint the existing wall surface to improve the aesthetic appearance and extend the life of the base material. For example, Patent Document 1 describes a method of applying a transparent coating agent as a topcoat material after polishing a deteriorated portion on the surface of a ceramic outer wall material coating layer.

Japanese Unexamined Patent Publication No. 2001-227138

However, even if the existing wall surface having an uneven pattern is repainted by the method described in the above patent document, the deterioration of the existing film cannot be sufficiently suppressed and the repainting effect is difficult to obtain. There is.

The present invention has been made in view of such problems, and provides a film forming method capable of suppressing deterioration of an existing film and maintaining aesthetics for a long period of time while utilizing the uneven pattern and color pattern of the existing wall surface. The purpose is to do.

In order to solve such a problem, the present inventor, as a result of diligent studies, came up with a film forming method of applying a specific topcoat material to an existing wall surface having an uneven pattern to form a film, and developed the present invention. It came to be completed.

That is, the present invention has the following features.
1. 1. This is a film forming method in which a topcoat material is applied to an existing wall surface that has deteriorated over time.
The existing wall surface has an uneven pattern on the surface and is provided with an existing coating film.
The topcoat material contains a non-aqueous solvent (A), a resin component (B), and a thickener (C).
The resin component (B) contains a polyol compound and a polyisocyanate compound, and contains an acrylic polyol compound having a weight average molecular weight of 40,000 or less as the polyol compound.
A film forming method, wherein the topcoat material has visible light transmittance and forms a film having an ultraviolet transmittance of 30% or less.
2. The existing wall surface has an uneven pattern on the surface and is composed of a plurality of plate-shaped wall materials having an existing coating film. The film forming method according to the above.

In the present invention, it is possible to obtain a finish that makes use of the uneven pattern and the color pattern of the existing wall surface by the new coating film formed from the specific topcoat material. Then, in the present invention, the new coating can sufficiently suppress the deterioration of the existing coating and maintain the aesthetic appearance for a long period of time.

Hereinafter, modes for carrying out the present invention will be described.

The present invention can be applied to existing wall surfaces such as buildings and civil engineering structures. Such an existing wall surface is composed of at least a base material and an existing coating film. Examples of the base material include concrete, mortar, metal, wood, glass and the like, and various plate-shaped wall materials and the like. Among these, as the plate-shaped wall material, for example, an inorganic hardened body containing any one of cement, calcium silicate, lime, gypsum and the like as a main component can be mentioned. Specific examples of such plate-shaped wall materials include cement boards, extruded boards, slate boards, PC boards, ALC boards, fiber-reinforced cement boards, siding boards, ceramic boards, calcium silicate boards, gypsum boards, and hard boards. Examples include wood piece cement board.

In the present invention, as an existing wall surface, a wall surface having an uneven pattern is targeted. Examples of the uneven pattern on the existing wall surface include a tile pattern, a brick pattern, a geometric pattern, a striped pattern, a lattice pattern, a polka dot pattern, a sand wall pattern, a yuzu skin pattern, a ripple pattern, and the like. , Graphic patterns and the like designed by animals and plants. Specifically, examples of the shape of the convex portion when the uneven pattern is viewed from the front include a square, a rectangle, a circle, an ellipse, a triangle, a rhombus, a polygon, and an indeterminate shape. Examples of the cross-sectional shape of the convex portion in the uneven pattern include a trapezoid, a square, a rectangle, a semicircle, a corrugated shape, a step shape, a triangle shape, and a chevron shape. Examples of the concave portion in the uneven pattern include those that are flat and form joints. The height difference between the concave portion and the convex portion may be constant or different in each portion, but is preferably 20 mm or less, more preferably about 1 to 15 mm. Such an uneven pattern may be applied to either one or both of the base material and the existing coating film.

In the existing wall surface in the present invention, an existing coating film is provided on the surface of the base material, and the existing wall surface can have various colors (single color or multicolor pattern). The existing coatings are various coatings that have already been coated on the base material by on-site coating, factory coating (line coating), or the like, and are at least selected from, for example, an organic coating, an inorganic coating, an organic-inorganic composite coating, and the like. One type of coating can be mentioned. Examples of existing coatings include colored coatings (enamel-based coatings, printing coatings, etc.), clear coatings, and laminated coatings thereof, which are formed by applying and curing various coating materials on a base material. .. Such a coating material may be, for example, any of a room temperature drying type, a room temperature curing type, a baking curing type, an ultraviolet (UV) curing type, an electron beam curing type and the like.

Examples of the binder of such a coating material include organic binders such as acrylic resin, polyurethane resin, epoxy resin, fluororesin, alkyd resin, and polyester resin, silicon resin, alkoxysilane, colloidal silica, and silicate. Examples thereof include an inorganic binder, an organic-inorganic composite binder such as an acrylic silicone resin, and the like.

In the present invention, in particular, the existing coating on the outermost surface includes an inorganic coating (a coating containing the inorganic binder), an organic-inorganic composite coating (a coating containing the organic-inorganic composite binder), and a fluororesin coating (including the fluororesin). It is suitable when it is one or more selected from (coating) and the like, and further, it can be suitably applied to these clear coatings.

The present invention can be applied as a remodeling method when the existing wall surface has deteriorated over time as described above. The degree of aging deterioration is not particularly limited, but a wall surface that has been used for about 5 years or more (further, 8 years or more) can be the subject of the present invention.

As the existing wall surface of the present invention, it is preferable that a plurality of plate-shaped wall materials having an uneven pattern on the surface and having an existing coating film are provided side by side. The present invention can obtain an advantageous effect when targeting an existing wall surface composed of such a plurality of plate-shaped wall materials. It is desirable that the uneven pattern is attached to at least the plate-shaped wall material itself.
The connecting portion between the plate-shaped wall materials may be filled with a sealing material or a dry joint material. In this case, a plurality of plate-shaped wall materials are provided side by side via a connecting portion, and a connecting portion is provided between the plate-shaped wall materials. The width of the connecting portion is preferably about 3 to 20 mm (more preferably 5 to 15 mm). The connecting portion is filled with a sealing material or a dry joint material.

In the present invention, an advantageous effect can be obtained when the existing wall surface is one in which the connecting portion between the plate-shaped wall materials is filled with a sealing material. The sealing material may be aged-deteriorated like the plate-shaped wall material, or may be newly cast before the topcoat material is applied.

General materials can be used as the sealing material, for example, silicone-based sealing material, modified silicone-based sealing material, polysulfide-based sealing material, modified polysulfide-based sealing material, acrylic urethane-based sealing material, polyurethane-based sealing material, SBR. Examples thereof include a silicone-based sealing material and a butyl rubber-based sealing material.
The filling method of the sealing material is not particularly limited, and for example, a known method using a gun, a spatula, or the like can be adopted.

Prior to filling the sealant, treatments such as filling the backup material and applying a primer may be performed in advance. As the backup material, for example, a foamed polyethylene-based backup material or the like can be used. As the primer, for example, a synthetic rubber-based primer, an acrylic-based primer, a urethane-based primer, an epoxy-based primer, a silicone resin-based primer, a silane-based primer, or the like can be used.

In the film forming method of the present invention, a topcoat material is applied (painted) to an existing wall surface that has deteriorated over time as described above.

The topcoat material in the present invention contains a non-aqueous solvent (A), a resin component (B), and a thickener (C), of which the resin component (B) contains a specific compound, and the ultraviolet transmittance and the like are specified. It is characterized by being within the range.

In the present invention, by using such a topcoat material, it is possible to obtain a finish utilizing the uneven pattern and the color pattern on the existing wall surface having the uneven pattern and the existing coating, and further, the existing coating. It is possible to form a new coating film that sufficiently suppresses the deterioration of the coating material and contributes to maintaining the aesthetic appearance for a long period of time. In the present invention, the life of the existing wall surface can be extended by such a new coating film. The mechanism of action in which such an effect is exerted is not limited to the following, but the topcoat material in the present invention can evenly form a thin and transparent film along the unevenness of the existing wall surface, and is also a non-aqueous solvent and a non-aqueous solvent. It is presumed that the action of the resin component and the like contributes to the development of excellent adhesion to the existing coating and the retention of the adhesion for a long period of time. In the present invention, such a newly formed coating enhances resistance to sunlight and water, and can obtain effects such as suppressing deterioration of the existing coating and maintaining aesthetic appearance for a long period of time.

Further, in the existing wall surface having an uneven pattern and having an existing coating film, the way of shining sunlight, the way of flowing water, the degree of retention, and the like are partially different depending on the shape of the unevenness and the like. Therefore, in the prior art, even after coating the topcoat material, deterioration progresses in a portion where the load due to sunlight or water is large, and there is a possibility that discoloration, cracks, etc. are locally caused. On the other hand, in the present invention, the new coating film formed from the specific topcoat material as described above is formed over the entire surface of the existing wall surface having an uneven pattern, and exhibits sufficient resistance to sunlight and water. It is considered that the deterioration of the coating film can be suppressed and the effect of maintaining the aesthetic appearance for a long period of time can be obtained.

Examples of the non-aqueous solvent (A) in the topcoat material include aliphatic solvents such as n-heptane, n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, and n-dodecane. In addition to hydrocarbon solvents, alicyclic hydrocarbon solvents such as methylcyclohexane and ethylcyclohexane, aliphatic hydrocarbon-containing mixed solvents such as mineral spirit, petroleum-based solvents such as petroleum ether, petroleum naphtha, solvent naphtha, and kerosine, isoparaffin Examples thereof include based solvents, alcohol solvents, ether alcohol solvents, ether solvents, ester solvents, ether ester solvents, ketone solvents and the like. These can be used alone or in combination of two or more.

The topcoat material in the present invention preferably contains a non-aqueous solvent having an aniline point of 12 to 70 ° C. as the non-aqueous solvent (A). It is considered that such a non-aqueous solvent contributes to the improvement of adhesion by slightly swelling or dissolving the existing coating film. As the non-aqueous solvent having an aniline point of 12 to 70 ° C., for example, one or more selected from an aliphatic hydrocarbon-containing mixed solvent such as mineral spirit, a petroleum-based solvent such as petroleum ether, petroleum naphtha, solvent naphtha, and kerosene can be used. Suitable. In the present invention, it is more preferable that the non-aqueous solvent (A) contains a non-aqueous solvent having an aniline point of 30 to 65 ° C., and a non-aqueous solvent having an aniline point of 30 to 65 ° C. is contained in the non-aqueous solvent (A). An embodiment containing 50 to 100% by weight is more preferable. The aniline point is a value measured by the method of JIS K2256. In the present invention, "α to β" is synonymous with "α or more and β or less".

The topcoat material in the present invention contains a polyol compound and a polyisocyanate compound as the resin component (B). Both of these components can be reacted and cured at the time of film formation to form a polyurethane resin film.

Among these, examples of the polyol compound include acrylic polyols, polyether polyols, polyester polyols, fluorine-containing polyols, polyisoprene polyols, carbonate polyols, and the like, and one or more of these can be used.

In the present invention, the polyol compound includes an acrylic polyol compound (B-1) having a weight average molecular weight of 40,000 or less (hereinafter, also referred to as “(B-1) component”). The component (B-1) contributes to the adhesion to the existing film, and is a beneficial component in terms of suppressing deterioration of the existing film, maintaining aesthetic appearance for a long period of time, and the like. The weight average molecular weight of the component (B-1) is 40,000 or less, preferably 3,000 to 35,000, more preferably 5,000 to 30,000, and even more preferably 8,000 to 25,000. The weight average molecular weight is a value obtained by measuring using gel permeation chromatography. It is desirable that such a component (B-1) is a soluble resin soluble in a non-aqueous solvent (A).

The glass transition point of the component (B-1) is preferably -40 to 60 ° C, more preferably -20 to 55 ° C. When the glass transition point is at least the above lower limit, it is suitable in terms of contamination suppression, aesthetic preservation, etc., and when the glass transition point is at least the above upper limit, it is possible to prevent cracking of the coating film, maintain aesthetic appearance, etc. Suitable. The glass transition temperature is a value obtained by the Fox calculation formula.

The hydroxyl value of the component (B-1) is preferably 10 to 200 KOH mg / g, more preferably 20 to 100 KOH mg / g. The hydroxyl value is a value represented by the number of mg of potassium hydroxide equimolar to the hydroxyl group contained in 1 g of the resin solid content.

As the component (B-1), for example, a (meth) acrylic acid alkyl ester, a hydroxyl group-containing monomer, and if necessary, other monomers are contained as constituent components, and a polymer of these can be used.

Of these, the (meth) acrylic acid alkyl ester is a compound having a (meth) acryloyl group and an alkyl group, and examples of the form of the alkyl group include linear, branched, and cyclic.

Examples of such (meth) acrylic acid alkyl ester include those having an alkyl group having 1 to 2 carbon atoms such as methyl (meth) acrylic acid and ethyl (meth) acrylic acid, or n (meth) acrylic acid. -Propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate , (Meta) neopentyl acrylate, (meth) t-pentyl acrylate, (meth) 1-ethylpropyl acrylate, 2-methyl butyl (meth) acrylate, 3-methyl butyl (meth) acrylate, (meth) acrylate n-hexyl, cyclohexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, 2-methylpentyl (meth) acrylate, 4-methylpentyl (meth) acrylate, n-heptyl (meth) acrylate, ( N-octyl acrylate, (meth) isooctyl acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, n-undecyl (meth) acrylate , (Meta) n-lauryl acrylate and the like having an alkyl group having 3 or more carbon atoms. These can be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (. Examples thereof include (meth) acrylic acid hydroxyalkyl esters such as 4-hydroxybutyl acrylate. These can be used alone or in combination of two or more.

Examples of the other monomers include a carboxyl group-containing monomer, an amino group-containing monomer, a pyridine-based monomer, a nitrile group-containing monomer, an amide group-containing monomer, an epoxy group-containing monomer, a carbonyl group-containing monomer, an alkoxysilyl group-containing monomer, and an fragrance. Examples thereof include a group monomer, an ultraviolet absorbing group-containing monomer, and a photostabilizing group-containing monomer. These can be used alone or in combination of two or more.

As the component (B-1), 20 weight by weight of a (meth) acrylic acid alkyl ester (m) having an alkyl group having 3 or more carbon atoms (hereinafter, also referred to as “(m) component”) is contained in the constituent component of the acrylic polyol. % Or more is preferable. As such a component (m), one having an alkyl group having 4 or more carbon atoms (more preferably 4 or more and 8 or less) is more preferable.

The ratio of the component (m) to the component (B-1) is preferably 20% by weight or more, more preferably 25 to 99% by weight, still more preferably 30 to 98% by weight. When the component (m) has the above ratio, resistance to water and the like can be enhanced, and it is also preferable in terms of suppressing deterioration such as discoloration and cracking and improving effects such as maintaining aesthetics.

The component (B-1) is a (meth) acrylic acid alkyl ester (m1) having an alkyl main chain having 4 or more carbon atoms as the (m) component in the resin constituent component (hereinafter, also referred to as “(m1) component”). Is preferably included. As such a (m1) component, the alkyl portion thereof is a linear or branched alkyl group (excluding cyclic), and the main chain (longest carbon linear chain) has 4 or more carbon atoms. Some can be used. If the acrylic polyol contains the component (m1), the effects such as resistance to water, suppression of deterioration such as cracks, and maintenance of aesthetics can be further enhanced.

The component (m1) has an alkyl main chain having 4 or more carbon atoms (preferably 4 or more and 8 or less) in the alkyl moiety. The alkyl moiety of the component (m1) may have various side chains (for example, an alkyl group having a smaller number of carbon atoms than the alkyl main chain) as long as it has such an alkyl main chain. Examples of the (m1) component include those satisfying such conditions among the above-mentioned (m) components, for example, n-butyl (meth) acrylate, 2-methylbutyl (meth) acrylate, and (meth). Isopentyl acrylate, 3-methylbutyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, n-pentyl (meth) acrylate, 2-methylpentyl (meth) acrylate, 4-methylpentyl (meth) acrylate , (Meta) n-hexyl acrylate, (meth) 2-ethylhexyl acrylate, (meth) n-heptyl acrylate, (meth) isooctyl acrylate, (meth) n-octyl acrylate, n (meth) acrylate -Nonyl, n-decyl (meth) acrylate, n-undecyl (meth) acrylate, n-lauryl (meth) acrylate and the like can be mentioned. These can be used alone or in combination of two or more.

Examples of the (m) component other than (m1) (hereinafter, also referred to as “(m2) component”) include n-propyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, and (meth). ) T-Butyl acrylate, neopentyl (meth) acrylate, t-pentyl (meth) acrylate, 1-ethylpropyl (meth) acrylate, cyclohexyl (meth) acrylate and the like. These can be used alone or in combination of two or more.

The weight ratio of the component (m1) to the component (m) can be expressed as "r". This "r" is a value calculated by the following formula.
[Formula] r = {Weight of (m1) component in resin component} / {Weight of (m) component in resin component}

R represented by the above formula is preferably 0.05 to 0.7, more preferably 0.1 to 0.5, and even more preferably 0.15 to 0.4.

The component (B-1) is preferably contained in the polyol compound in an amount of 30% by weight or more, more preferably 50% by weight or more, and further preferably 60% by weight in terms of solid content. It is particularly desirable that it is contained in an amount of% by weight or more. In the present invention, only the acrylic polyol compound can be used as the polyol compound.

In the present invention, the polyol compound can include the component (B-1) and a fluorine-containing polyol. The fluorine-containing polyol is a polyol compound having a fluorine atom and a hydroxyl group. By using a fluorine-containing polyol, resistance to sunlight and water can be enhanced, which is preferable in terms of suppressing deterioration such as discoloration and cracking, and improving effects such as maintaining aesthetics. Such a fluorine-containing polyol can be obtained, for example, by copolymerizing a fluorine-containing monomer such as a fluoroolefin or a fluoroalkyl group-containing acrylic monomer, a hydroxyl group-containing monomer, and another monomer, if necessary. it can. The acrylic polyol having a fluorine atom is included in the fluorine-containing polyol.

Among these, as fluoroolefins, for example, vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, 1,1,3,3,3-pentafluoropropylene, 2,2,3,3-tetra Fluoropropylene, 1,1,2-trifluoropropylene, 3,3,3-trifluoropropylene, chlorotrifluoroethylene, bromotrifluoroethylene, 1-chloro-1,2-difluoroethylene, 1,1-dichloro- Examples thereof include 2,2-difluoroethylene. Examples of the fluoroalkyl group-containing acrylic monomer include perfluoromethyl (meth) acrylate, perfluoroisononylmethyl (meth) acrylate, and 2-perfluorooctylethyl (meth) acrylate. These can be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer in the fluorine-containing polyol include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, and hydroxypentyl vinyl ether; ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, and triethylene glycol monoallyl ether. Hydroxyallyl ethers such as; (meth) acrylic acid hydroxyalkyl esters similar to those described above can be mentioned. These can be used alone or in combination of two or more.

Examples of other monomers in the fluorine-containing polyol include (meth) acrylic acid alkyl ester, carboxyl group-containing monomer, amino group-containing monomer, pyridine-based monomer, nitrile group-containing monomer, amide group-containing monomer, epoxy group-containing monomer, and carbonyl. Examples thereof include a group-containing monomer, an alkoxysilyl group-containing monomer, an aromatic monomer, an ultraviolet-absorbing group-containing monomer, and a photostable group-containing monomer. These can be used alone or in combination of two or more.

In the embodiment containing the component (B-1) and the fluorine-containing polyol, the resistance to sunlight and water can be further enhanced, sufficient adhesion and the like can be ensured for a long period of time, and the effect of the present invention can be improved. It is suitable in terms of conversion. In this case, the component (B-1) is preferably contained in the polyol compound in an amount of 30 to 99% by weight, more preferably 50 to 95% by weight, and 60 to 90% by weight in terms of solid content. It is more desirable that it is contained in an amount of 65 to 85% by weight. The fluorine-containing polyol is preferably contained in the polyol compound in an amount of 1 to 70% by weight, more preferably 5 to 50% by weight, and even more preferably 10 to 40% by weight in terms of solid content. It is particularly desirable that it is contained in an amount of 15 to 35% by weight.

The polyisocyanate compound has two or more isocyanate groups in one molecule, and crosslinks with the above-mentioned polyol compound to form a film.

Examples of the polyisocyanate compound include toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI), polypeptide MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and water. Addition XDI, hydrogenation MDI, etc., or derivatives thereof (for example, compounds obtained by a urethanization reaction, an allophanation reaction, an isocyanurateization reaction, etc.) include those having an allophanate group, an allophanate group, and an isocyanurate group. You can also use what you have. These can be used alone or in combination of two or more.

The polyisocyanate compound preferably has an average number of functional groups of 2 to 3, more preferably 2.0 to 2.6, and even more preferably 2.1 to 2.5. By using such a polyisocyanate compound, resistance to water and the like can be enhanced, and effects such as discoloration, suppression of deterioration such as cracks, and maintenance of aesthetics can be further enhanced. Further, the use of such a polyisocyanate compound is particularly advantageous when the existing wall surface has a sealing material, and suppresses swelling, cracking, peeling, etc. of the coating film in the vicinity of the connecting portion filled with the sealing material. However, it can contribute to the effect of maintaining the finish for a long period of time.

The number average number of functional groups of the polyisocyanate compound is a value obtained by the following formula. In the following formula, the number average molecular weight of polyisocyanate is a value measured by gel filtration chromatography (GPC). The NCO content is the ratio of NCO groups in the polyisocyanate compound expressed in% by mass. 42 in the formula is the molecular weight of the NCO group.
<Formula> Number average number of functional groups = (number average molecular weight x NCO content (%) / 100) / 42

The mixing ratio of the polyisocyanate compound may be set in consideration of the equivalent ratio of the isocyanate groups of the polyisocyanate compound to the hydroxyl group of the polyol compound, that is, the NCO / OH ratio. The NCO / OH ratio is preferably 0.6 to 1.4, more preferably 0.8 to 1.2. With such a ratio, the effect of the present invention can be sufficiently obtained.

The resin component (B) can contain a compound having a reactive silyl group in addition to the above-mentioned polyol compound and polyisocyanate compound. Examples of such a compound include a reactive silyl group-containing vinyl compound, a tetraalkoxysilane compound, an alkylalkoxysilane compound, a silane coupling agent, and the like, or a compound derived from these (for example, a condensate, a modified product, or a copolymerization). One or more selected from compounds, copolymers, etc.) can be used. It is considered that the compound having a reactive silyl group contributes to the improvement of adhesion due to its cross-linking reactivity.

The reactive silyl group is, for example, one in which one or more functional groups selected from an alkoxyl group, a hydroxyl group, a phenoxy group, a mercapto group, an amino group, a halogen and the like are bonded to a silicon atom. Of these, an alkoxysilyl group in which an alkoxyl group is bonded to a silicon atom and / or a silanol group in which a hydroxyl group is bonded to a silicon atom are preferable.

Examples of the reactive silyl group-containing vinyl compound include γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, and γ-. (Meta) Acryloxypropylmethyldiethoxysilane and the like can be mentioned.

The reactive silyl group-containing vinyl compound can be used in the form of a resin (for example, acrylic silicone resin) obtained by copolymerization with other monomers. Examples of such monomers include (meth) acrylic acid alkyl esters, hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, pyridine-based monomers, nitrile group-containing monomers, amide group-containing monomers, and epoxy group-containing monomers. Examples thereof include a carbonyl group-containing monomer, a fluorine-containing monomer, an aromatic monomer, an ultraviolet-absorbing group-containing monomer, and a photostable group-containing monomer. These can be used alone or in combination of two or more.

Examples of the tetraalkoxysilane compound include tetramethoxysilane, tetraethoxysilane, and tetrabutoxysilane.

Examples of the alkylalkoxysilane compound include methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and butyl. Trimethoxysilane, butyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dipropyldimethoxy Examples thereof include silane, dipropyldiethoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldibutoxysilane, methylphenyldimethoxysilane, and methylphenyldiethoxysilane.

Examples of the silane coupling agent include epoxy group-containing silanes such as γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyltriethoxysilane, and β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane. Coupling agent, N-β (aminoethyl) γ-aminopropylmethyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane and other amino group-containing silane coupling agents, as well as isocyanate group-containing Examples thereof include a silane coupling agent, an isocyanurate group-containing silane coupling agent, and an acid anhydride group (carboxyl group) -containing silane coupling agent.

The compound having a reactive silyl group is contained in the solid content of the resin component (B) within a range of preferably 0.1 to 30% by weight, more preferably 0.3 to 20% by weight in terms of _{SiO 2.} Can be done. When the mixing ratio of the compound having a reactive silyl group is within such a range, the adhesion between the existing coating film and the topcoat material coating film can be further enhanced, and peeling of the coating film can be prevented for a long period of time. It is suitable in terms of maintaining aesthetics.

The SiO ₂ conversion is expressed by the weight of a compound having a Si—O bond that remains _{as silica (SiO 2) when it is completely hydrolyzed and then fired at 900 ° C.} In general, tetraalkoxysilanes, alkylalkoxysilanes and the like have the property of reacting with water to undergo a hydrolysis reaction to form silanols, and further causing a condensation reaction between silanols or with silanols and alkoxy. When this reaction is carried out to the ultimate, it becomes _{silica (SiO 2).} These reactions
RO (Si (OR) ₂ O) _n R + (n + 1) H ₂ O → nSiO ₂ + (2n + 2) ROH
(R indicates an alkyl group. N is an integer.)
It is expressed by the reaction formula. _{The SiO 2} conversion in the present invention is a conversion of the amount of the silica component remaining based on this reaction formula.

When a compound having a reactive silyl group is used as the resin component (B), a curing catalyst can also be used in combination. Examples of the curing catalyst include organic tin compounds, organic aluminum compounds, organic titanate compounds, acidic compounds, amine compounds, alkaline compounds and the like, and these can be used alone or in combination of two or more.

Examples of the thickener (C) in the topcoat material include organic bentonite, fine powder silica, surface-treated calcium carbonate, amido wax, hydrogenated castor oil wax, benzylidene sorbitol, metal soap, polyethylene oxide, polymerized vegetable oil, and amine polycarboxylic acid. Examples include salt. These can be used alone or in combination of two or more.

The mixing ratio of the thickener (C) is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the solid content of the resin component (B). If the mixing amount of the thickener (C) is within such a range, the topcoat material can be easily applied evenly along the unevenness of the existing wall surface, the deterioration of the existing film can be suppressed, and the aesthetic appearance can be maintained for a long period of time. The effect of the present invention can be stably obtained.

In the topcoat material, the solid content of the resin component (B) is preferably 25 to 75% by weight, more preferably 35 to 70% by weight in the topcoat material. The solid content of the resin component (B) in the topcoat material {the weight ratio of the resin component (B) to the weight of the topcoat material at the time of painting} is such a ratio, so that the existing wall surface The topcoat material can be applied evenly along the unevenness of the above, and it is possible to form a new coating with excellent performance in suppressing deterioration of the existing coating and maintaining the aesthetic appearance for a long period of time while making the best use of the uneven pattern. It becomes. The solid content is a value measured by the method of JIS K5601-1-2, and the heating temperature is 105 ° C. and the heating time is 60 minutes.

The topcoat material in the present invention forms a film having visible light transmission. As a result, a transparent film can be formed, and it is possible to obtain a finish that makes use of the colors (single color, multicolor pattern, etc.) of the existing film surface. The visible light transmission may be such that the existing coating surface can be visually recognized, and the coating may be colorless or transparent or colored transparent, and may be glossy or matte (7-minute gloss, 5-minute gloss, 3 minutes gloss). (Including gloss, etc.) may be used. The colored transparent film can be formed by, for example, a topcoat material containing a coloring pigment, a dye, or the like. The matte coating can be formed by, for example, a topcoat material containing an extender pigment, a matting agent, and the like.

The degree of visible light transmittance can be indicated by the visible light transmittance. The visible light transmittance is preferably 30% or more, more preferably 35 to 100%, still more preferably 40 to 95%. The visible light transmittance is a value measured by using a spectrophotometer for a film having a thickness of 30 μm and a wavelength of 580 nm (the transmittance is 100% in the case of no film (air)). is there.

In order to obtain such visible light transmission, for example, the ratio of the coloring pigment in the topcoat material may be set low. The color pigment ratio in the topcoat material is preferably 10% by weight or less, more preferably 5% by weight or less, still more preferably 0 to 3% by weight. It is also preferable that the topcoat material does not contain a coloring pigment.

The topcoat material in the present invention forms a film having an ultraviolet transmittance of 30% or less, preferably 20% or less, and more preferably 0 to 15%. In the present invention, when the ultraviolet transmittance is within the above range, resistance to sunlight and the like can be enhanced, and effects such as deterioration suppression such as discoloration and cracks and maintenance of aesthetics can be obtained. The ultraviolet transmittance is a value obtained by measuring the transmittance of light having a wavelength of 350 nm with a spectrophotometer for a film having a thickness of 30 μm (the transmittance is 100% in the case of no film (air)). ..

As a means for obtaining such ultraviolet transmittance, for example,
(1) Use a topcoat material containing a resin component having an ultraviolet absorbing group.
(2) Use a topcoat material containing an ultraviolet absorber.
(3) Use a topcoat material containing UV-shielding powder.
And so on. These means may be adopted alone or in combination.

In the above (1), for example, as the resin component (B), a compound or the like containing an ultraviolet absorbing group-containing monomer in the resin component may be used. In this case, the ratio of the ultraviolet absorbing group-containing monomer in the compound is preferably 0.05 to 10% by weight, more preferably 0.1 to 5% by weight.

Examples of the ultraviolet absorber (excluding the compound having a polymerizable unsaturated double bond) in (2) above include a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a triazine-based ultraviolet absorber, and a salicylate-based ultraviolet absorber. Examples thereof include agents, cyanoacrylate-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, malonic acid ester-based ultraviolet absorbers, and oxalic acid anilide-based ultraviolet absorbers. Among these, examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, and 2-hydroxy-4-n. -Octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2,2'-dihydroxy -4-methoxybenzophenone, 2,2'-dihydroxy-4,4'dimethoxybenzophenone, 2,2', 4,4'-tetrahydroxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-hydroxy-4- Examples thereof include methoxy-2'-carboxybenzophenone and 2-hydroxy-4-stearyloxybenzophenone. Examples of the benzotriazole-based ultraviolet absorber include 2- (2-hydroxy-5-t-butylphenyl) -2H-benzotriazole and 3- (2H-benzotriazole-2-yl) -5- (1,1). -Dimethylethyl) -4-hydroxyalkyl ester, 2- (2H-benzotriazole-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2- (2H-benzotriazole-2) -Il) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3-tetramethylbutyl) phenol, methyl 3- (3- (2H-benzotriazole-2-yl) Examples thereof include reaction products of -5-t-butyl-4-hydroxyphenyl) propionate and polyethylene glycol. Examples of the triazine-based ultraviolet absorber include 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine-2-yl) -5-hydroxyphenyl derivative and 2- (2). , 4-Dihydroxyphenyl) -4,6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidate ester reaction product, 2,4-bis " 2-Hydroxy-4-butoxyphenyl] -6- (2,4-dibutoxyphenyl) -1,3-5-triazine, etc. These can be used alone or in combination of two or more. The mixing ratio of the resin component (B) is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the solid content of the resin component (B).

As the ultraviolet shielding powder in (3) above, a powder having the ability to absorb and / or reflect ultraviolet rays can be used, and for example, alumina, zinc oxide, barium sulfate, precipitated barium sulfate, calcium carbonate, magnesium carbonate, etc. Aluminum hydroxide, magnesium hydroxide, titanium oxide, magnesium oxide, zinc oxide, boron nitride, bismuth oxychloride, zinc phosphate, mica, cold water stone, talc, diatomaceous soil, white clay, kaolin, clay, porcelain clay, barite powder, silica sand, Examples thereof include talc powder, white carbon, metal powder, and organic resin powder. These can be used alone or in combination of two or more. The average particle size of the UV-shielding powder is preferably 1 to 200 nm. In the above (3), it is desirable to set the mixing ratio of the ultraviolet shielding powder within a range in which visible light transmission can be ensured.

In addition to the above components, the topcoat material in the present invention is, if necessary, known additives such as aggregates, colored grains, coloring pigments, extender pigments, dyes, and luster, as long as the effects of the present invention are not significantly impaired. Erasers, thickeners, wetting agents, dehydrating agents, leveling agents, plasticizers, fibers, antifreeze agents, film-forming aids, preservatives, fungicides, fungicides, antibacterial agents, dispersants, antifoaming agents , A light stabilizer, an antioxidant, an adhesion imparting agent, a low-staining agent, a hydrophilic agent, a water repellent, a cross-linking agent, a curing accelerator, a catalyst, a solvent and the like.

The topcoat material of the present invention can be produced by uniformly mixing the above-mentioned component (A), (B) component, (C) component, and if necessary, the above-mentioned various components by a conventional method. The form of the topcoat material can be, for example, a one-component type, a two-component type, or a multi-component type. A preferable example of the form of the topcoat material is, for example, a two-component form composed of a main agent containing at least a polyol compound and a curing agent containing at least a polyisocyanate compound.

The topcoat material in the present invention preferably forms a film having an elongation rate of 20% or more (more preferably 40% or more, further preferably 50% or more, particularly preferably 60% or more). In the present invention, when the elongation rate is within the above range, resistance to water and the like can be enhanced, and effects such as deterioration suppression such as discoloration and cracking and maintenance of aesthetics can be further enhanced. The upper limit of the elongation rate is preferably 300% or less, more preferably 200% or less. Since the upper limit of the elongation rate is within such a range, it is preferable in terms of stain resistance and the like.

The elongation rate in the present invention is a value (elongation rate at 23 ° C.) measured by the method of "elongation test at standard time" of JIS A6909 "7.26 elongation test". However, as the test piece, a piece having a dry film thickness of 80 μm is used.

In the present invention, a new coating film is formed by applying (painting) such a topcoat material. The topcoat material can be applied directly to the existing wall surface, but various pretreatments can be performed as needed. Examples of the pretreatment include removal of an existing coating film that is significantly deteriorated, removal of contaminants by high-pressure washing, repair with putty, filler, etc., restoration of the surface shape, and the like. When a new sealing material is placed on the existing wall surface, it is desirable to apply the topcoat material approximately 2 to 10 days after the sealing material is placed.

As the topcoat material, one kind or two or more kinds of topcoat materials satisfying the above conditions can be used. In the present invention, such a topcoat material can be overcoated. For example, one type of topcoat material may be applied multiple times, or two or more types of topcoat material may be applied repeatedly. When recoating, the film may be dried at appropriate intervals.

A known coating tool can be used for coating the topcoat material. As the painting tool, for example, a spray, a roller, a brush, or the like can be used. The topcoat material can be appropriately diluted before use for painting.

The coating amount at the time of coating the topcoat material is preferably 100 to 600 g / m ² , and more preferably 150 to 500 g / m ² . By setting the lower limit of the coating amount of the topcoat material to the above value, the new coating is sufficiently resistant to sunlight and water, discoloration due to the existing coating surface, deterioration suppression such as cracks, and long-term aesthetics. It is suitable in terms of maintaining properties. When the upper limit of the coating amount of the topcoat material is the above value, it is possible to obtain a finish utilizing the uneven pattern of the existing coating surface. When the topcoat material is applied repeatedly, it is desirable that the total amount of application is within the above range. The number of times the topcoat material is applied is preferably 1 to 3 times.

The viscosity of the topcoat material at the time of coating is preferably 0.1 to 10 Pa · s, more preferably 0.2 to 5 Pa · s. When the viscosity of the topcoat material is within such a range, the effect of the present invention can be stably obtained. The viscosity referred to here is a value obtained by measuring the viscosity at 20 rpm (guideline value at the fourth rotation) with a BH type viscometer, and the measurement temperature is 23 ° C.

The drying after the topcoat material is applied may be carried out at room temperature (preferably 0 to 50 ° C., more preferably 5 to 45 ° C.), and may be heated if necessary.

The film thickness of the new coating formed by such a topcoat material (in the case of recoating, the total film thickness after recoating) is preferably 30 μm or more, more preferably 50 μm or more, still more preferably 60 μm or more, particularly preferably. Is more than 65 μm, most preferably 70 μm or more. The upper limit of the film thickness of the new coating film is not particularly limited, but is preferably 300 μm or less, more preferably 250 μm or less, and further preferably 200 μm or less. The film thickness in the present invention is the dry film thickness, and when one or more types of topcoat materials are applied repeatedly, it is the total dry film thickness after the application.

Examples are shown below to clarify the features of the present invention.

The following topcoat materials 1 to 14 were prepared as the topcoat materials. The following raw materials (polyols 1 to 5) were used as the acrylic polyol compound.

-Polycarbonate 1: Soluble acrylic polyol (acrylic acid alkyl ester, methacrylic acid acrylic ester, methacrylic acid hydroxyalkyl ester copolymer solution, (m) component 62% by weight, (m1) component 18% by weight in the resin constituents, r = 0.29,
Hydroxy group value 50 KOHmg / g, weight average molecular weight 15000, solid content 50% by weight, medium: mineral spirit (aniline point 42 ° C)
-Polycarbonate 2: Soluble acrylic polyol (acrylic acid alkyl ester, methacrylic acid acrylic ester, methacrylic acid hydroxyalkyl ester copolymer solution, (m) component 62% by weight, (m1) component 18% by weight in the resin constituents, r = 0.29,
Hydroxy group value 50 KOHmg / g, weight average molecular weight 26000, solid content 50% by weight, medium: mineral spirit (same as above)
-Polycarbonate 3: Soluble acrylic polyol (acrylic acid alkyl ester, methacrylic acid acrylic ester, methacrylic acid hydroxyalkyl ester copolymer solution, (m) component 62% by weight, (m1) component 18% by weight in the resin constituents, r = 0.29,
Hydroxy group value 50 KOHmg / g, weight average molecular weight 36000, solid content 50% by weight, medium: mineral spirit (same as above)
Polycarbonate 4: Soluble acrylic polyol (acrylic acid alkyl ester, methacrylic acid acrylic ester, methacrylic acid hydroxyalkyl ester copolymer solution, (m) component 62% by weight, (m1) component 50% by weight in the resin constituents, r = 0.81,
Hydroxy group value 50 KOHmg / g, weight average molecular weight 15000, solid content 50% by weight, medium: mineral spirit (same as above)
Polycarbonate 5: Soluble acrylic polyol (acrylic acid alkyl ester, methacrylic acid acrylic ester, methacrylic acid hydroxyalkyl ester copolymer solution, (m) component 62% by weight, (m1) component 18% by weight in the resin constituents, r = 0.29,
Hydroxy group value 50 KOHmg / g, weight average molecular weight 49000, solid content 50% by weight, medium: mineral spirit (same as above)

(Topcoat material 1)
A main agent containing polyol 1, an ultraviolet absorber, a light stabilizer, a thickener (amaide wax), an antifoaming agent, and a solvent naphtha (aniline point 13 ° C.).
Polyisocyanate 1 (1,6-diisocyanatohexane derivative, number average number of functional groups 2.2, solid content 100% by weight), tetraalkoxysilane compound (isobutyl alcohol modified product of tetramethoxysilane condensate), and mineral spirit ( Mixture with hardener containing (same as above) (NCO / OH ratio 1.0).
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 120%.

(Topcoat material 2)
Main agent containing polyol 4, UV absorber, light stabilizer, thickener (same as above), defoamer, and solvent naphtha (same as above).
Mixture with hardener containing polyisocyanate 2 {1,6-diisocyanatohexane derivative, number average number of functional groups 2.6, solid content 100% by weight}, tetraalkoxysilane compound (same as above), and mineral spirit (same as above) (NCO / OH ratio 1.0).
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 61%, ultraviolet transmittance: 6%, elongation rate: 30%.

(Top coating material 3)
Main agent containing polyol 1, UV absorber, light stabilizer, thickener (same as above), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 66%, ultraviolet transmittance: 24%, elongation rate: 120%. The topcoat material 3 was prepared so that the amount of the ultraviolet absorber mixed was smaller than that of the topcoat material 1 so that the ultraviolet transmittance had the above value.

(Topcoat material 4)
Main agent containing polyol 1, UV absorber, light stabilizer, thickener (same as above), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 0.1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 120%.

(Topcoat material 5)
Polyol 1, polyol 6 {fluorine-containing polyol solution, hydroxyl value 40 KOHmg / g, solid content 50% by weight, medium: mineral spirit (same as above)}, UV absorber, light stabilizer, thickener (amaide wax), defoaming Agent, and main agent containing solvent naphtha (same as above),
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 1: polyol 6 = 80: 20 (solid content weight ratio),
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 63%, ultraviolet transmittance: 5%, elongation rate: 130%.

(Topcoat material 6)
Main agent containing polyol 1, polyol 6 (same as above), UV absorber, light stabilizer, thickener (amide wax), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 1: polyol 6 = 70: 30 (solid content weight ratio),
Solid content of resin component in topcoat material: 38% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 63%, ultraviolet transmittance: 5%, elongation rate: 130%.

(Topcoat material 7)
Main agent containing polyol 1, polyol 6 (same as above), UV absorber, light stabilizer, thickener (amide wax), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 1: polyol 6 = 70: 30 (solid content weight ratio),
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 5%, elongation rate: 130%.

(Topcoat material 8)
Main agent containing polyol 2, polyol 6 (same as above), UV absorber, light stabilizer, thickener (amide wax), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 2: polyol 6 = 70: 30 (solid content weight ratio),
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 130%.

(Topcoat material 9)
Main agent containing polyol 3, polyol 6 (same as above), UV absorber, light stabilizer, thickener (amide wax), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 3: Polypoly 6 = 70: 30 (solid content weight ratio),
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 130%.

(Top coating material 10)
Main agent containing polyol 1, polyol 6 (same as above), UV absorber, light stabilizer, thickener (amide wax), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 1: polyol 6 = 50: 50 (solid content weight ratio),
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 140%.

(Topcoat material 11)
Main agent containing polyol 1, polyol 6 (same as above), UV absorber, light stabilizer, thickener (amide wax), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 1: polyol 6 = 30: 70 (solid content weight ratio),
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 150%.

(Topcoat material 12)
Main agent containing polyol 1, polyol 6 (same as above), UV absorber, light stabilizer, thickener (amide wax), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Polyol 1: polyol 6 = 99.2: 0.8 (solid content weight ratio),
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 120%.

(Topcoat material 13)
Main agent containing polyol 5, UV absorber, light stabilizer, thickener (same as above), defoamer, and solvent naphtha (same as above).
A mixture (NCO / OH ratio 1.0) with a curing agent containing polyisocyanate 1 (same as above), tetraalkoxysilane compound (same as above), and mineral spirit (same as above).
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 3% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 64%, ultraviolet transmittance: 6%, elongation rate: 120%.

(Topcoat material 14)
A mixture of polyol 1, UV absorber, light stabilizer, thickener (same as above), defoamer, and solvent naphtha (same as above), and mineral spirit (same as above).
Solid content of resin component in topcoat material: 45% by weight, ratio of compound having reactive silyl group: 0% by weight (SiO ₂ conversion), mineral spirit ratio in all non-aqueous solvent: 80% by weight, solvent naphtha ratio: 20% by weight, thickener ratio: 1 part by weight in solid content with respect to 100 parts by weight of solid content of the resin component, visible light transmittance: 65%, ultraviolet transmittance: 6%, elongation rate: 60%.

○ Preparation of test specimen As an existing wall surface, a gray ceramic siding boat that has deteriorated due to outdoor exposure (the surface has tile joint-like convex parts and concave parts (joints), and the convex parts have an irregular uneven pattern, and the outermost layer. A coating film having an inorganic clear film) was prepared. To the entire surface of the existing wall, and spraying at topcoat material to wiping amount 110g / ^{m 2} (Example 5 In 30 g / ^{m 2),} after 2 hours drying, again smeared weight 110g / ^{m 2} (Example In No. 5, a test piece was prepared by spray coating at ^{30 g / m 2) and drying and curing for 7 days.} The painting and curing steps were all carried out under standard conditions (temperature 23 ° C., relative humidity 50%).

(Test 1)
After 14 days of immersion in water, the test piece prepared by the above method was cross-cut with a cutter knife into the coating film of each part of the uneven pattern, and the adhesiveness was evaluated by attaching a tape to the cross-cut portion and peeling it off. The evaluation was performed as "A" for those with no peeling, "B" for those that were generally good but with some peeling, and "C" for those with a lot of peeling. It was.

(Test 2)
The test piece prepared by the above method was exposed to an accelerated weather resistance tester (Metal Weather; manufactured by Daipra Wintes Co., Ltd.) for 500 hours, and then the appearance of the test piece surface changed (gloss, color, floating, peeling, etc.). The state of cracks) was observed. The evaluation was made in three stages (excellent; A> B) in which the change in appearance was compared with the test piece before exposure, and "A: no change" and "C: decreased gloss, discoloration, floating, peeling or cracking progress". >C; inferior).

(Test 3)
After the above test 2, the exposure with the accelerated weathering tester was carried out for another 300 hours (800 hours in total), and the appearance change (gloss, color, floating, peeling, cracking state) of the surface of the test piece was observed. The evaluation was made in three stages (excellent; A> B) in which the change in appearance was compared with the test piece before exposure, and "A: no change" and "C: decreased gloss, discoloration, floating, peeling or cracking progress". >C; inferior).

(Test 4)
The test piece prepared by the above method is exposed to the outdoors for 3 months, the appearance change due to the dirt on the surface of the test piece is observed, and the one with a slight degree of dirt is designated as "A"(excellent; A). >B>C; inferior).

(Test results)
The test results are shown in Tables 1 and 2. In Examples 1 to 13, the new coating formed from each topcoat material makes it possible to obtain a finish that makes use of the uneven pattern and color pattern of the existing wall surface, and good results can also be obtained in Tests 1 to 4. It was.

Claims (2)

This is a film forming method in which a topcoat material is applied to an existing wall surface that has deteriorated over time.
The existing wall surface has an uneven pattern on the surface and is provided with an existing coating film.
The topcoat material contains a non-aqueous solvent (A), a resin component (B), and a thickener (C).
The resin component (B) contains a polyol compound and a polyisocyanate compound, and contains an acrylic polyol compound having a weight average molecular weight of 40,000 or less as the polyol compound.
A film forming method, wherein the topcoat material has visible light transmittance and forms a film having an ultraviolet transmittance of 30% or less. The film forming method according to claim 1, wherein the existing wall surface has an uneven pattern on the surface and is composed of a plurality of plate-shaped wall materials having an existing film.