JP5846771B2 - Coating method - Google Patents

Description

  The present invention relates to a novel coating method.

  Conventionally, various heat insulating base materials are used for the wall surface of a building. In such a heat-insulating base material, in order to enhance its aesthetics, a coating film by a finish coating material or the like is often provided (for example, JP-A-10-101458).

  However, since the wall surface made of such a heat-insulating base material is exposed to the outdoors for a long time, it may be contaminated by the influence of rainfall, dust, etc., and the aesthetics of the corner may be impaired. In particular, when significant contamination occurs partially in one wall surface, the influence on the aesthetic deterioration is great. Furthermore, in the part where such contamination occurs, the degree of absorption of sunlight increases, and heat conduction to the lower layer is difficult to occur, so that a temperature rise is likely to be caused. The local temperature rise on the heat insulating substrate may induce swelling or peeling of the coating.

JP-A-10-101458

  The present invention has been made in view of the above-mentioned problems. A coating is provided on the surface of a heat-insulating base material to enhance aesthetics, and further, local temperature rise of the coating is alleviated, swelled and peeled off. The purpose is to suppress the occurrence of such problems.

  As a result of intensive studies to achieve the above object, the present inventor has conceived that a specific colored coating (A) and a transparent coating (B) are provided on the heat insulating substrate, and completes the present invention. It reached.

That is, the present invention has the following characteristics.
1. A method of coating a heat insulating substrate,
The heat-insulating substrate has an uneven film on its surface and has an existing film having a colored region of two or more colors,
On the surface of the heat insulating base material, a colored coating (A) in which an infrared reflective powder and aminosilane are mixed in an acrylic polymer matrix is provided,
On the colored coating (A), silica having an average primary particle diameter of 1 to 200 nm is immobilized with a polymer, and the solid content weight ratio of the silica and the polymer is 0.8: 1 to 5: 1. A coating method comprising providing a transparent coating (B).
2. The heat-insulating base material is mixed with colored regions having a color difference (ΔE) of 5 or more. The coating method described in 1.
3. The colored coating (A) is a mixture of infrared reflective powder, aminosilane, and dimethylsiloxane in an acrylic polymer matrix. Or 2. The method of coating according to.

  Above 1. According to the invention which concerns on this, aesthetics improve by providing a colored film (A) and a transparent film (B) on the surface of a heat insulating base material. Furthermore, the synergistic action of these coatings alleviates local temperature rise and suppresses the occurrence of problems such as swelling and peeling. Above 1. In the invention according to the above, such an effect can be exhibited over a long period of time.

2. In the invention which concerns on this, what has an uneven | corrugated pattern on the surface as a heat insulating base material is object.
When a heat-insulating substrate having a concavo-convex pattern is exposed to the outdoors for a long period of time, contamination on the surface tends to be noticeable particularly near the recesses. That is, in the vicinity of the concave portion, an increase in temperature tends to occur with a decrease in aesthetics. Such a temperature rise may promote the occurrence of defects in the coating. Moreover, in the heat-insulating base material having a concavo-convex pattern, since the way of sunlight is different in each of the recesses or projections, there is a portion where the degree of temperature increase is large, and the defect of the coating tends to occur in that portion. .
2. In the invention according to the present invention, by providing the heat insulating base material with the colored film (A) and the transparent film (B), the aesthetics of the whole base material is enhanced, and the local temperature rise is alleviated. In addition, the occurrence of defects in the coating can also be suppressed.

3. above. In the invention which concerns, what has an existing film on the surface as a heat insulating base material is made into object.
When a coating is provided for the purpose of refurbishment or the like on a heat-insulating substrate having an existing coating, problems such as swelling and peeling may easily occur due to aging degradation of the existing coating.
3. above. In the invention according to the present invention, by providing the heat-insulating base material with the colored coating (A) and the transparent coating (B), the aesthetics can be enhanced, and the occurrence of problems such as swelling and peeling can be suppressed.

4. above. In the invention according to the invention, as the colored coating (A), an acrylic polymer matrix in which infrared reflective powder and aminosilane are mixed is used.
4. above. According to the invention which concerns on this, the adhesiveness of the film with respect to a heat insulating base material etc. can improve, and generation | occurrence | production of malfunctions, such as peeling and a swelling, can fully be suppressed.

5. above. In the invention according to the invention, as the colored coating (A), an acrylic polymer matrix in which infrared reflective powder, aminosilane, and dimethylsiloxane are mixed is used.
5. above. In the invention which concerns, by employ | adopting such a colored film (A), the crack generation | occurrence | production in a film is fully suppressed and adhesiveness is further improved.

It is sectional drawing which shows an example of this invention coating method. It is sectional drawing which shows another example of this invention coating method.

Hereinafter, modes for carrying out the present invention will be described.
FIG. 1 is a cross-sectional view showing an example of the coating method of the present invention.

The heat insulating substrate 1 in the present invention has a low thermal conductivity and has a heat insulating property. As the heat insulating substrate 1, specifically, one having a thermal conductivity of 0.5 W / (m · K) or less can be used. Examples of such a heat-insulating substrate 1 include lightweight mortar, lightweight concrete, foamed concrete board, calcium silicate board, pearlite cement board, rock wool board, glass wool thermal insulation board, and a composite thereof. . The heat insulating substrate 1 may be a substrate having a coating with a thermal conductivity of 0.5 W / (m · K) or less on a substrate such as general mortar, concrete, slate plate or the like.
As the heat-insulating substrate 1, one having a flat surface or one having an uneven pattern on the surface can be used. In the present invention, an advantageous effect can be obtained particularly when the heat-insulating substrate 1 having an uneven pattern is targeted.
Examples of the concavo-convex pattern in the heat-insulating base material 1 include various patterns such as tile-like patterns, brick-like patterns, geometric patterns, striped patterns, lattice patterns, polka dots, etc. Examples include graphic patterns. Specifically, examples of the shape of the convex portion when the concavo-convex pattern is viewed from the front include shapes such as a square, a rectangle, a circle, an ellipse, a triangle, a rhombus, a polygon, and an indefinite shape. Moreover, as a cross-sectional shape of the convex part in an uneven | corrugated pattern, a trapezoid, square, a rectangle, a semicircle, a waveform, a staircase shape, a triangle, a mountain shape etc. are mentioned, for example. The recesses in the concavo-convex pattern are usually flat and preferably form joints. The height difference between the concave portion and the convex portion may be constant or different in each convex portion, but is preferably 20 mm or less, more preferably about 1 to 15 mm.

As the heat insulating substrate 1, one having an existing coating 2 on its surface can be used (FIG. 2). In the present invention, an advantageous effect can be obtained even when the heat insulating base material 1 having such an existing coating is used.
Furthermore, in this invention, what has a concavo-convex pattern and has 2 or more types of coloring area | regions as the heat insulating base material 1 can be made into object. Such a heat insulating substrate 1 has an existing coating 2 having two or more different colors on its surface. The color of each colored region is not particularly limited, but the present invention can provide a particularly advantageous effect when colored regions having greatly different brightness, saturation, hue, and the like are mixed. Specific examples of such a heat insulating substrate 1 include a mixture of colored regions having a color difference (ΔE) of 5 or more (more preferably 10 or more). In the present invention, a particularly advantageous effect can be obtained when the heat-insulating substrate 1 having existing coatings of different colors in the concave and convex portions is used.

  When the heat-insulating base material 1 has a concavo-convex pattern and two or more colored areas, a difference occurs in the degree of absorption of sunlight in each colored area, and a temperature rise occurs in a portion where the degree of absorption is large. It becomes easy. In particular, when a colored region that easily absorbs sunlight is formed in the vicinity of the concave portion, there is a possibility that the increase in temperature may be promoted by overlapping with the sunlight absorbing action by the pollutant. The present invention effectively works to improve such problems.

  The present invention can be applied as a retrofit specification when the heat insulating base material 1 having the existing coating 2 has deteriorated over time. The degree of aging deterioration is not particularly limited, but those used as wall surfaces for about 5 years or more (more preferably 8 years or more) can be the subject of the present invention.

In this invention, the wall surface by which the sealing material or the dry joint material was filled in the connection part of the some heat insulation base materials 1 can be made into object. In this case, the plurality of heat insulating base materials 1 are provided side by side through a connecting portion, and a connecting portion is provided between the heat insulating base materials 1. 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, a particularly advantageous effect can be obtained when the sealing material is filled in the connecting portion between the heat insulating substrates 1.
The sealing material may be one that has deteriorated over time in the same manner as the heat insulating base material 1, or may be newly placed before the colored coating (A) is formed. In the present invention, particularly excellent effects can be exhibited when a sealing material is newly placed.

Common sealants can be used, such as silicone sealants, modified silicone sealants, polysulfide sealants, modified polysulfide sealants, acrylic urethane sealants, polyurethane sealants, SBR. And the like, and butyl rubber sealing material.
The method of filling the sealing material is not particularly limited, and for example, a known method using a gun or a spatula can be employed.

In the present invention, particularly when a modified silicone sealant is used as the sealant, an excellent effect can be obtained.
The modified silicone sealant is a sealant containing a modified silicone resin. This modified silicone resin has an organic resin as the main chain and has at least one reactive silyl group at the terminal or side chain. Examples of the organic resin constituting the main chain of the modified silicone resin include a polyether polymer, a polyester polymer, an ether / ester block copolymer, an ethylenically unsaturated compound polymer, and a diene compound polymer. Examples of the reactive silyl group include an alkoxysilyl group and a silanol group.

The polyether polymer in the modified silicone resin has an alkylene oxide repeating unit. Examples of the alkylene oxide include ethylene oxide and propylene oxide.
The polyester polymer has an ester of a carboxyl group-containing compound as a repeating unit. Examples of the carboxyl group-containing compound include acetic acid, propionic acid, maleic acid, phthalic acid, citric acid, pyruvic acid, and lactic acid.
The ether / ester block copolymer has both the repeating unit of the polyether polymer and the repeating unit of the polyester polymer.
The ethylenically unsaturated compound polymer contains an ethylenically unsaturated compound as a monomer component. Examples of the ethylenically unsaturated compound include ethylene, propylene, isobutene, (meth) acrylic acid ester, styrene, vinyl acetate and the like. Specific examples of the ethylenically unsaturated compound polymer include, for example, an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, a polyisobutylene, a polyacrylic acid ester, and a polymethacrylic acid. Examples include esters.
The diene compound polymer has a diene compound as a monomer component. Examples of the diene compound include butadiene, chloroprene, isoprene and the like. Specific examples of the diene compound polymer include, for example, polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, ethylene-butadiene copolymer, polyisoprene, styrene-isoprene copolymer, and isobutylene-isoprene copolymer. Examples of the polymer include polychloroprene, styrene-chloroprene copolymer, and acrylonitrile-chloroprene copolymer.

In the present invention, even when a non-bleed type sealing material is used, an excellent effect can be obtained. The non-bleed type sealing material referred to here is one having a plasticizer content of 5% by weight or less (preferably not containing a plasticizer) in the sealing material. Examples of the plasticizer include phthalic acid esters such as dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, and di (2-ethylhexyl) phthalate; aliphatic dibasic acid esters such as dioctyl adipate and dioctyl sebacate; Examples thereof include phosphoric esters such as zircyl phosphate and tributyl phosphate, and halogenated aliphatic compounds such as chlorinated paraffin. The molecular weight of these plasticizers is usually less than 500.
Examples of the non-bleed type sealing material include an acrylic urethane sealing material, a polyurethane sealing material, and a modified silicone sealing material that satisfy the above conditions. In the present invention, when a non-bleed type modified silicone sealant is used, a particularly excellent effect can be obtained.

  Prior to filling with the sealing material, treatments such as back-up material filling and primer application 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 primer, an acrylic primer, a urethane primer, an epoxy primer, a silicone resin primer, a silane primer, or the like can be used.

In the present invention, a colored coating (A) containing infrared reflective powder and a transparent coating (B) containing silica having an average primary particle diameter of 1 to 200 nm are provided on the surface of the heat insulating substrate 1 as a decorative coating. Such a colored coating (A) and transparent coating (B) enhance aesthetics while making use of the concavo-convex pattern when the heat insulating substrate 1 has the concavo-convex pattern. Moreover, when the heat insulating base material 1 has the existing coating 2, it becomes a decorative coating for refurbishment.
In this invention, the temperature rise by sunlight irradiation is suppressed by the infrared reflective action of a colored film (A). Furthermore, since the transparent coating (B) prevents the adhesion of pollutants, the temperature rise caused by the sunlight absorption of the pollutants is suppressed. In the present invention, these synergistic effects can suppress problems such as swelling and peeling in the decorative coating.

  In addition to such an action, in the present invention, an increase in the temperature of the transparent coating (B) can also be suppressed by the infrared reflecting action of the colored coating (A). If the temperature of the transparent film (B) rises excessively, the original anti-contamination action may not be exhibited due to softening of the film, or the anti-contamination action may be impaired early due to a decrease in the durability of the film. On the other hand, in this invention, the temperature rise of a transparent film (B) is suppressed by the effect | action of the said colored film (A), and sufficient pollution prevention effect is exhibited over a long period of time. Thereby, the aesthetics based on the color etc. of a colored film (A) are maintained over a long period, and the temperature rise resulting from sunlight absorption of a pollutant can also be avoided for a long period.

  As the colored coating (A), those in which infrared reflective powder is mixed in a polymer matrix are suitable. Examples of the resin that forms the polymer matrix include acrylic resin, urethane resin, vinyl acetate resin, urethane resin, silicone resin, fluorine resin, acrylic vinyl acetate resin, acrylic urethane resin, and acrylic silicon resin. Species or two or more can be used.

  Examples of the infrared reflective powder include aluminum flake, titanium oxide, barium sulfate, zinc oxide, iron oxide, calcium carbonate, silicon oxide, magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, alumina, and iron-chromium composite oxide. , Manganese bismuth composite oxide, manganese yttrium composite oxide, and the like, and one or more of these can be used. The ratio of the infrared reflective powder is preferably 3 to 800 parts by weight, more preferably 5 to 600 parts by weight, based on 100 parts by weight of the polymer matrix, in terms of solid content.

  The colored coating (A) may further contain an infrared transmitting powder. A wide variety of color tones can be expressed by appropriately combining these infrared transmitting powders. Examples of the infrared transmitting powder include perylene pigment, azo pigment, yellow lead, petal, vermilion, titanium red, cadmium red, quinacridone red, isoindolinone, benzimidazolone, phthalocyanine green, phthalocyanine blue, cobalt blue, Induslen blue, ultramarine blue, bitumen and the like can be mentioned, and one or more of these can be used. The ratio of the infrared transmitting powder is preferably 1 to 200 parts by weight, more preferably 2 to 100 parts by weight with respect to 100 parts by weight of the polymer matrix in terms of solid content.

In the present invention, a preferred embodiment of the colored coating (A) includes a mixture of infrared reflective powder and aminosilane (hereinafter referred to as “colored coating (A1)”) in an acrylic polymer matrix.
In this invention, the adhesiveness to the heat insulating base material 1 can be improved by employ | adopting such a colored film (A1). This is particularly effective when the heat insulating substrate 1 has the existing coating 2. For example, when the heat-insulating substrate 1 has different colored regions, differences in the deterioration state are likely to occur in each colored region, which may adversely affect the adhesion, but if a colored coating (A1) is used, Adhesion to such colored regions can be sufficiently ensured. Moreover, in this invention, adhesiveness with the below-mentioned colored film (A ') or transparent film (B) can also be improved by use of a colored film (A1). Furthermore, when the wall surface which has a sealing material in the connection part of the heat insulating base materials 1 is made into object, a colored film (A1) is excellent also in adhesiveness with a sealing material.

The acrylic polymer matrix is a resin matrix formed of an acrylic polymer. This acrylic polymer is a polymer of a monomer mixture containing at least one alkyl (meth) acrylate.
Specific examples of the (meth) acrylic acid alkyl ester include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, n-amyl ( (Meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate, Examples include cyclohexyl (meth) acrylate, phenyl (meth) acrylate, and benzyl (meth) acrylate. These can be used alone or in combination of two or more.

  The constituent ratio of the (meth) acrylic acid alkyl ester in the monomer mixture is preferably 30% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more. Although an upper limit is not specifically limited, Preferably it is 99.8 weight% or less, More preferably, it is 99.5 weight% or less, More preferably, it is 99 weight% or less.

  In the acrylic polymer, a monomer copolymerizable with the above (meth) acrylic acid alkyl ester can be copolymerized. Examples of such monomers include vinyl acetate, vinyl chloride, styrene and the like, in addition to monomers having a functional group such as carboxyl group, amino group, amide group, epoxy group, carbonyl group, and hydroxyl group.

  The glass transition temperature of the acrylic polymer is preferably -20 to 80 ° C, more preferably -10 to 60 ° C. The glass transition temperature is a value obtained by the Fox calculation formula.

Aminosilane is a compound having an amino group and a reactive silyl group. Examples of the reactive silyl group include an alkoxysilyl group and a silanol group.
Examples of aminosilane include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, and N- (β-aminoethyl) -γ-. Aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyldimethylmethoxysilane, γ-aminopropyldimethylethoxysilane, N- (β-aminoethyl) -γ- Aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldiethoxysilane, N- (6-aminohexyl) aminopropyltrimethoxysilane, N- (6-aminohexyl) aminopropyltriethoxy Silane, N- (β-amino ester ) -Γ-aminoisobutyltrimethoxysilane, N- (β-aminoethyl) -γ-aminoisobutylmethyldimethoxysilane, γ-aminopropyldiisopropyltrimethoxysilane, γ-aminopropyldiisopropyltriethoxysilane, γ-aminopropyl Methylbis (trimethylsiloxy) silane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, N- Benzyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltriethoxysilane, 3- (m-aminophenoxy) propyltrimethoxysilane, 3- (m-aminophenoxy) propyltriethoxysilane M-aminophenyltrimethoxysilane, m-aminophenyltriethoxysilane, p-aminophenyltrimethoxysilane, p-aminophenyltriethoxysilane, aminophenyltrimethoxysilane, aminophenyltriethoxysilane, γ-aminopropyl Tris (methoxyethoxyethoxy) silane, γ-aminopropyltris (trimethylsiloxy) silane, 2-aminoethylaminomethylbenzyloxydimethylsilane, (aminoethylaminomethyl) phenethyltrimethoxysilane, N-vinylbenzyl-γ-aminoro One or more selected from pyrtriethoxysilane and the like can be mentioned. Among these, aminosilane having two or more (preferably two) amino groups in one molecule is preferable.
The weight ratio of aminosilane is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the acrylic polymer matrix in terms of solid content.

In the present invention, as the colored coating (A), an acrylic polymer matrix in which infrared reflective powder, aminosilane and dimethylsiloxane are mixed (hereinafter referred to as “colored coating (A2)”) can be used. In this invention, it becomes possible by using the colored film (A2) containing such a component to improve the adhesiveness with the heat insulating base material 1, the followability to the heat insulating base material 1, and the like. When targeting a wall surface having a sealing material at the connecting portion between the heat-insulating base materials 1, the colored coating (A2) is also advantageous for improving the adhesion with the sealing material, while following the displacement of the sealing material, The ability to alleviate the change can also be imparted. Furthermore, the colored coating (A2) also contributes to improving the adhesion with the later-described colored coating (A ′) or the transparent coating (B).
By such an action, in the colored coating (A2), peeling of the coating, cracks, and the like can be sufficiently suppressed. Such an effect is presumed to be achieved by the synergistic action of dimethylsiloxane and aminosilane.
As the acrylic polymer and aminosilane, the same ones as described above can be used.

Dimethylsiloxane in the colored coating (A2) is synthesized using dimethyldialkoxysilane, dimethylsiloxane oligomer or the like as a raw material. Examples of dimethyldialkoxysilane include dimethyldimethoxysilane and dimethyldiethoxysilane. Examples of the dimethylsiloxane oligomer include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and tetradecamethylcycloheptasiloxane. The average molecular weight of dimethylsiloxane is preferably 10,000 or more, more preferably 50,000 or more.
The weight ratio of dimethylsiloxane is preferably 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, based on 100 parts by weight of the acrylic polymer matrix, in terms of solid content.

  The colored coating (A) can be formed by applying and drying a coating material containing the above components. The covering material may contain various components other than the above components as long as the effects of the present invention are not significantly impaired. Examples of such components include matting agents, thickeners, film-forming aids, leveling agents, wetting agents, plasticizers, antifreezing agents, pH adjusting agents, antiseptics, antifungal agents, and antialgal agents. Antibacterial agents, dispersants, antifoaming agents, adsorbents, fibers, crosslinking agents, ultraviolet absorbers, antioxidants, catalysts and the like can be mentioned.

When applying the said coating | covering material to the heat insulating base material 1, well-known coating tools, such as a brush, a roller, a spray, can be used, for example. When a sealing material is newly placed on the connecting portion between the heat-insulating base materials 1, the coating material may be applied approximately 2 to 10 days after the sealing material is placed.
In the present invention, the colored coating (A) can be formed by applying the coating material to the entire surface of the heat insulating substrate 1. The coating amount of the coating material is preferably about 10 to 300 g / m ^{2 in} terms of solid content.

  In the present invention, the colored film (A) having a different color from the colored film (A) with respect to a part of the region on the colored film (A) and containing an infrared reflecting powder and / or an infrared transmitting powder ( A ′) can be provided. By laminating such colored coatings, a desired appearance finish having two or more colored areas can be obtained. In addition, the design properties of the existing coating 2 can be reproduced.

  As the colored coating (A ′), a polymer matrix in which infrared reflecting powder and / or infrared transmitting powder is mixed is preferable. As the polymer matrix, the infrared reflecting powder, and the infrared transmitting powder, the same materials as described in the colored coating (A) can be used. As the colored coating (A ′), one containing either one or both of infrared reflecting powder and infrared transmitting powder can be used. In the present invention, as the coating material for forming the colored film (A ′), the same coating material as that for the colored film (A) can be used.

The colored coating (A ′) can be formed by applying and drying the coating material. As a coating instrument, well-known things, such as a brush, a roller, a spray, a wrinkle, can be used, for example.
What is necessary is just to apply | coat the coating material which forms a colored film (A ') to a one part area | region on a colored film (A). For example, when the heat-insulating base material 1 has a concavo-convex pattern, the colored coating (A ′) can be formed by applying a coating material to either one of the convex portion and the concave portion. The color of the colored coating (A ′) can be appropriately set in consideration of the finished appearance and the like. Moreover, what is necessary is just to set the coating amount suitably according to the material to be used.

  The transparent coating (B) is provided on the outermost surface of the decorative coating. As the transparent coating (B) in the present invention, those in which silica having an average primary particle diameter of 1 to 200 nm is immobilized with a polymer are suitable.

Among these, silica exhibits a superior anti-contamination effect due to the high hardness of the particles themselves and the fact that they have many silanol groups on the surface of the particles.
The average primary particle diameter of silica is usually 1 to 200 nm, preferably 5 to 100 nm. Within this range, a plurality of silicas having different average primary particle sizes can be used in combination. When the average primary particle diameter of silica is larger than 200 nm, the specific surface area becomes small, and silanol groups are also reduced, so that the antifouling property becomes insufficient. When the average primary particle diameter is smaller than 1 nm, the silica itself becomes unstable, so it is not practical. In addition, the average primary particle diameter said here is a value measured by the light-scattering method.

The silica of the transparent coating (B) is preferably derived from a silica sol, and further derived from a water-dispersible silica sol having a pH of 5.0 or more and less than 8.5 (preferably 6.0 or more and 8.0 or less). Is more preferred.
Such a neutral type water-dispersible silica sol can be produced using a silicate compound as a raw material. Examples of the silicate compound include tetramethoxysilane, tetraethoxysilane, tetra n-propoxysilane, tetraisopropoxysilane, tetra n-butoxysilane, tetraisobutoxysilane, tetra sec-butoxysilane, tetra t-butoxysilane, tetra Examples thereof include phenoxysilane and the condensates thereof. In addition, alkoxysilane compounds other than the above silicate compounds, alcohols, glycols, glycol ethers, fluorine alcohols, silane coupling agents, polyoxyalkylene group-containing compounds, and the like can also be used.

  Various resins can be used as the polymer for immobilizing the silica. Specifically, for example, acrylic resin, urethane resin, vinyl acetate resin, urethane resin, silicon resin, fluorine resin, acrylic vinyl acetate resin, acrylic urethane resin, acrylic silicon resin, and the like, one or two of these can be mentioned. The above can be used. As such a resin, a water-soluble resin and / or a water-dispersible resin is preferable.

  The solid content weight ratio (silica: polymer) of silica and polymer in the transparent coating (B) is preferably 0.5: 1 to 5: 1, more preferably 0.8: 1 to 4: 1, and even more preferably. 1: 1 to 3: 1. With such a ratio, a sufficient anti-contamination effect can be obtained, and the adhesion with the lower layer film can be enhanced, so that the effect of the present invention is stably exhibited over a long period of time.

The transparent film (B) can be formed by applying and drying a coating material containing the above components. What is necessary is just to apply | coat this coating | covering material on the whole surface on a colored film (A). As a coating instrument, well-known things, such as a brush, a roller, and a spray, can be used, for example. Coating with the amount of the coating material for forming the transparent film (B) is in terms of the solid content, preferably 0.1 to 50 g / ^{m 2,} more preferably 0.5 to 20 g / ^{m 2.}

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

<Test I>
(Test specimen production)
A lightweight concrete plate exposed to an accelerated weathering tester was prepared as a substrate. This lightweight concrete board has a tile-like uneven pattern on the surface, a black acrylic coating on the recesses, and a light brown acrylic coating on the projections, and the projections are more deteriorated than the recesses. It was in a state of progress. The thermal conductivity is 0.2 W / (m · K).
The coating material A is spray-coated on the entire surface of the substrate at a coating amount of 80 g / m ² (solid content), and after curing for 1 day, the coating material B is sprayed at a coating amount of 3 g / m ² (solid content). The test plate was obtained by painting and curing for 7 days. The coating and curing were all performed under standard conditions (temperature 23 ° C., relative humidity 50%).

As the covering material A, those shown below were used.
Covering material A1: acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): aminosilane (N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane) : Infrared reflective powder (iron-chromium composite oxide) = 98: 2: 8 (solid content weight ratio) black aqueous coating material.
Covering material A2: acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): aminosilane (γ-aminopropyltrimethoxysilane): infrared reflective powder (iron chromium) Composite oxide) = 98: 2: 8 (solid weight ratio) black aqueous coating material.
Covering material A3: acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): aminosilane (N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane) : Dimethylsiloxane (composition of dimethylsiloxane oligomer): Black aqueous coating material of infrared reflecting powder (iron-chromium composite oxide) = 78: 20: 2: 8 (solid content weight ratio).
Covering material A4: acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): dimethyl siloxane (composition of dimethyl siloxane oligomer): infrared reflective powder (iron chromium) Complex oxide) = 80: 20: 8 (solid weight ratio) black aqueous coating material.
Covering material A5: acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): silane compound (γ-glycidoxypropyltrimethoxysilane): infrared reflective powder (Iron-chromium composite oxide) = 98: 2: 8 (solid content weight ratio) black aqueous coating material.
Covering material A6: acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): silane compound (polyether chain-containing trimethoxysilane): infrared reflective powder (iron Chromium composite oxide) = 98: 2: 8 (solid content weight ratio) black aqueous coating material.
Covering material A7: Acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): Silane compound (vinyltrimethoxysilane): Infrared reflective powder (iron chromium composite oxidation) Product) = 98: 2: 8 (solid weight ratio) black aqueous coating material.
Covering material A8: acrylic polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate copolymer resin, glass transition temperature 5 ° C.): dimethylsiloxane (composition of dimethylsiloxane oligomer): infrared absorbing powder (carbon black ) = 80: 20: 8 (solid weight ratio) black aqueous coating material.

As the coating material B, the following materials were used.
Coating material B1: Silica (water-dispersible silica sol, pH 7.6, average primary particle size 27 nm): acrylic silicon polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate-γ-methacryloyloxypropyltrimethoxysilane copolymer) Resin, glass transition temperature 18 ° C.) = 1.5: 1 (solid weight ratio) aqueous dispersion.
Covering material B2: An aqueous dispersion of acrylic silicon polymer (methyl methacrylate-n-butyl acrylate-2-ethylhexyl acrylate-γ-methacryloyloxypropyltrimethoxysilane copolymer resin, glass transition temperature 18 ° C.).

(Test method)
The test plate obtained by the above-mentioned method was immersed in a contaminant suspension (concentration 1% by weight) for 2 hours, pulled up and allowed to stand in a standard state for 24 hours, and then washed and dried. The test plate was irradiated with an infrared lamp for 8 hours at a distance of 60 cm and then immersed in water at 23 ° C. for 16 hours for a total of 10 cycles, and the appearance change was visually observed. The evaluation was performed in four stages (A>B>C> D) where “A” indicates no abnormality (swelling, peeling, etc.) and “D” indicates that abnormality is clearly observed.

(Test results)
Table 1 shows the coating materials used in the above test and the test results. In Test Examples 1 to 7, good results were obtained.

<Test II>
(Test specimen production)
A base material similar to that in the above <Test I> is prepared, and two base materials are provided side by side, and a modified silicone sealant (resin component: alkoxysilyl group-containing polyether polymer) is provided at the connecting portion (width 10 mm) between the plates. And a plasticizer content of less than 1% by weight were used as the base material to be coated.
The entire surface of the substrate thus obtained is spray-coated with a coating material A at a coating amount of 80 g / m ² (solid content), and after curing for 1 day, a coating material B is coated with a coating amount of 3 g / m ^2. (Solid content) was spray coated and cured for 7 days. All painting and curing were performed under standard conditions.

(Test method)
-Adhesion test After immersing the test specimen (300 x 150 mm) prepared by the above method in warm water at 50 ° C for 72 hours, put a crosscut with a cutter knife on the coating of each part (connecting part, concave part, convex part), Adhesion was evaluated by affixing a tape to the crosscut portion and peeling it off. The evaluation was performed in three stages (A>B> C) where “A” indicates that no abnormality was observed and “C” indicates that peeling was observed.

-Followability test About the test body (300x150mm) produced by the said method, the surface state when it displaced 30% in a horizontal direction with a tension tester in a standard state was observed, and followability was evaluated. The evaluation was performed in three stages (A>B> C) where “A” indicates no abnormality and “C” indicates abnormality such as cracking or peeling.

(Test results)
Table 2 shows the coating materials used in the above test and the test results. In Test Examples 11 to 13, generally good results were obtained.

1: Insulating base material 2: Existing coating A: Colored coating (A)
B: Transparent coating (B)

Claims (3)

A method of coating a heat insulating substrate,
The heat-insulating substrate has an uneven film on its surface and has an existing film having a colored region of two or more colors,
On the surface of the heat insulating base material, a colored coating (A) in which an infrared reflective powder and aminosilane are mixed in an acrylic polymer matrix is provided,
On the colored coating (A), silica having an average primary particle diameter of 1 to 200 nm is immobilized with a polymer, and the solid content weight ratio of the silica and the polymer is 0.8: 1 to 5: 1. A coating method comprising providing a transparent coating (B). The coating method according to claim 1, wherein the heat insulating base material includes a colored region having a color difference (ΔE) of 5 or more. The coating method according to claim 1 or 2, wherein the colored coating (A) is a mixture of infrared reflective powder, aminosilane, and dimethylsiloxane in an acrylic polymer matrix.

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