JP4877941B2 - Coating laminate - Google Patents

Description

  The present invention relates to a coating film laminate used as a surface makeup for buildings, civil engineering structures, and the like.

  2. Description of the Related Art Conventionally, various gloss grades have been provided as surface cosmetic paints for buildings and civil engineering structures. Among these, paints capable of forming a matte coating film have been gaining popularity in recent years because they can provide a calm and unique texture.

  As the matte paint, paints defined in JIS K5663 “Synthetic resin emulsion paint” are generally used. In addition, architectural finish coating materials specified in JIS A6909, for example, thin finish coating materials such as ricin paint, thick finish coating materials such as stucco paint, other stone finish finish coating materials, sandstone finish finish coating materials, etc. Some of them have a matte appearance, and are widely used as thick film type materials capable of forming an uneven pattern.

  By the way, in recent years, in urban areas and the like, oily pollutants and the like are floating in the atmosphere due to exhaust gas from automobiles and the like. Even in the matte paint as described above, these contaminants may be deposited on the surface of the coating film, resulting in a loss of aesthetics.

As an antifouling treatment agent applicable to the coating film surface, Patent Document 1 describes a composition comprising a resin, an oxide sol organic solvent, and water.
However, when the antifouling agent as disclosed in Patent Document 1 is applied to the matte coating film, the finish may be different from the initial glossy state. In addition, a phenomenon that the hue of the coating film changes to black, that is, a so-called wet color may occur. Furthermore, interference unevenness in which a part of the film has a rainbow color may occur. As described above, the antifouling agent as disclosed in Patent Document 1 has a problem that the texture of the original matte coating film is easily impaired. In the first place, such an antifouling agent is designed as a material for a glossy coating film such as a coating film on an automobile outer plate, and it is not assumed that the object is a matte coating film.

  The present invention has been made in view of the above-described problems, and an object thereof is to improve the stain resistance of the coating film surface while maintaining the texture of the matte coating film.

WO99 / 54414

  As a result of intensive studies to achieve the above object, the present inventor has come up with a coating laminate in which a specific coating layer mainly composed of an organic resin and silica is provided on the surface of the matte coating layer. The present invention has been completed.

That is, the present invention has the following characteristics.
1. A coating layer is provided on the surface of the matte coating layer in a state where the matting coating layer is visible,
The coating layer includes an organic resin and silica in a solid content weight ratio of 100: 50 to 100: 500,
Silica contained in the coating layer is an aggregate derived from silica sol having an average primary particle diameter of 1 to 200 nm,
The coating amount of the coating layer is 0.1 to 50 g / m ² in terms of solid content.
2. The silica sol is a water-dispersible silica sol having a pH of 5.0 or more and less than 8.5. The coating film laminated body of description.

  ADVANTAGE OF THE INVENTION According to this invention, the stain resistance of the coating-film surface can be improved, maintaining the texture of a matt coating film.

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

  The coating laminate of the present invention has a matte coating layer provided with a coating layer, and is mainly exposed to surface cosmetics such as buildings and civil engineering structures, particularly to wind and rain. It can be preferably applied to cosmetics for exterior surfaces.

  Of these, the matte coating layer is formed of a matte paint. Examples of such matte paints include paints defined in JIS K5663 “Synthetic Resin Emulsion Paint”. This type of paint is commonly referred to as a flat paint. Other matte coatings include thin finish coating materials such as lysine paints, thick finish coating materials such as stucco paints, etc. as defined in JIS A6909, other stone finish finish coating materials, and sandstone finish finish coating materials There are various finishing coating materials for buildings. Such a building finish coating material can be used as a thick film type material capable of forming an uneven pattern.

The matte paint film layer can be formed by applying and drying a matte paint on the surface of a base material such as a building or a civil engineering structure. The matte paint film layer may exist in advance as an old paint film on the surface of a base material such as a building or a civil engineering structure.
The degree of “matte” in the matte coating layer can be defined by its specular gloss. The specular gloss (measuring angle 60 degrees) of the matte coating layer is usually 20 or less, preferably 15 or less, more preferably 10 or less.

  The coating film laminate of the present invention has a coating layer provided on the surface of the matte coating layer described above. This coating layer is provided in a state where the matte coating layer is visible. That is, the hue and concavo-convex pattern of the matte coating film hardly change regardless of the presence or absence of the coating layer.

The coating layer in the present invention is formed by a coating solution containing an organic resin and silica.
Of these, the organic resin is a component mainly responsible for immobilizing silica. Examples of the organic resin include cellulose, polyvinyl alcohol, bio gum, galactomannan derivative, alginic acid derivative, vinyl acetate resin, vinyl chloride resin, epoxy resin, acrylic resin, urethane resin, acrylic silicon resin, fluorine resin, or a composite thereof. A system etc. are mentioned, These 1 type (s) or 2 or more types can be used. These may have crosslinking reactivity. As the form of the organic resin, a water-soluble resin and / or a water-dispersible resin (resin emulsion) is preferable.

  Silica in the coating layer is an aggregate derived from silica sol having an average primary particle diameter of 1 to 200 nm. Such silica exhibits stain resistance by the action of polar groups such as silanol groups, and further suppresses the occurrence of bottom gloss, wet color, interference interference, etc. due to the formation of aggregates, and improves the texture of matte coatings. It is a component that plays a role of holding.

  The average primary particle diameter of the silica sol is usually 1 to 200 nm, preferably 5 to 100 nm. Within this range, a plurality of silica sols having different average primary particle sizes can be used in combination. When the average primary particle diameter of the silica sol is larger than 200 nm, the specific surface area becomes small and silanol groups are reduced, so that the stain resistance is insufficient. When the average primary particle size is smaller than 1 nm, the silica sol itself becomes unstable, so that it is not practical. In addition, the average primary particle diameter said here is a value measured by the light-scattering method.

  As the silica sol, 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 suitable. The silica sol prepared at such pH can exhibit an excellent antifouling effect due to abundant silanol groups on the particle surface. Moreover, the aqueous coating liquid which hardly contains an organic solvent can be obtained by the combination of water-soluble resin and / or water-dispersible resin, and water-dispersible silica sol.

  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. As the medium of the water-dispersible silica sol, water and / or a water-soluble solvent can be used. Examples of the water-soluble solvent include alcohols, glycols, glycol ethers and the like.

  The silica in the coating layer is a secondary aggregate of the primary particles of such a silica sol. The secondary flocculation of the silica sol can be advanced by appropriately adjusting the concentration of the coating liquid forming the coating layer, the charged state, and the like. For example, if the solid content concentration in the coating liquid is set sufficiently low, silica sols approach each other in the drying process of the coating liquid, and a secondary aggregate is generated by the interaction. For these reasons, it is desirable that the solid content concentration of the coating liquid is usually set to 10% by weight or less (preferably 5% by weight or less, more preferably 3% by weight or less). Furthermore, using two or more different resins in combination as the organic resin constituting the coating liquid is also an effective means for producing secondary aggregates. Examples include acrylic resin and urethane resin, acrylic silicon resin and urethane resin, acrylic resin and epoxy resin, acrylic silicon resin and epoxy resin, acrylic resin and biogum, and a combination of acrylic silicon resin and biogum. When two types of resins are used in combination, one resin may be adjusted to be less than 1/9 of the other resin in the solid content weight ratio.

  The solid content weight ratio of the organic resin and silica in the coating layer is usually 100: 50 to 100: 500 (preferably 100: 80 to 100: 400, more preferably 100: 100 to 100: 300). Within such a range, excellent antifouling performance can be obtained while maintaining the texture of the matte coating film. When the amount of silica is too small in this solid content ratio, the texture of the matte coating film is liable to be damaged, and a sufficient effect cannot be obtained in terms of stain resistance. When there is too much silica, the silica of the coating layer may be detached over time, and the anti-staining effect may be impaired. In addition, cracks are likely to occur in the coating layer.

  Components other than the organic resin and silica can be appropriately mixed in the coating solution for forming the coating layer. Such components include, for example, thickeners, leveling agents, wetting agents, plasticizers, film-forming aids, antifreezing agents, pH adjusting agents, preservatives, antifungal agents, antialgae agents, antibacterial agents, dispersions Agents, antifoaming agents, ultraviolet absorbers, antioxidants, pigments, catalysts, crosslinking agents and the like. The pH of the coating solution is desirably 5.0 to less than 8.5 (preferably 6.5 to 8.0) from the viewpoint of the stability of the coating solution.

When forming the coating layer, coating means such as spray coating, brush coating, and roller coating can be appropriately employed.
The coating amount of the coating layer is 0.1 to 50 g / m ² (preferably 0.5 to 20 g / m ² ) in terms of solid content. When the coating amount is less than 0.1 g / m ^{2, the} effect of improving the stain resistance is not obtained, and when it is more than 50 g / m ² , the fine unevenness on the matte coating surface is flattened, The texture of the matte paint film is easily damaged. In addition, since the coating layer in the present invention does not cause defects such as uneven gloss even if the coating amount varies slightly within the above range, the efficiency of the coating operation can be improved.

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

(Aqueous coating solution A)
Acrylic silicone resin emulsion (solid content 50% by weight), water-soluble urethane resin (solid content 35% by weight), water-dispersible silica sol (pH 7.6, solid content 20% by weight, average primary particle size 27 nm) The mixture was mixed at a ratio of 92: 8: 125, and water was added thereto to prepare an aqueous coating liquid A having a solid content of 2% by weight and a pH of 7.2. This aqueous coating liquid A was spray-coated on black paper at a coating amount (solid content) of 3 g / m ² , dried in a standard state for 24 hours, and the coating film was observed with a scanning electron microscope. Aggregation was confirmed.

(Aqueous coating solution B)
Acrylic silicon resin emulsion (solid content 50% by weight), water-soluble epoxy resin (solid content 100% by weight), water-dispersible silica sol (pH 7.6, solid content 20% by weight, average primary particle size 27 nm) The mixture was mixed at a ratio of 92: 8: 125, and water was added thereto to prepare an aqueous coating solution B having a solid content of 2% by weight and a pH of 7.2. This aqueous coating solution B was spray-coated on black paper at a coating amount (solid content) of 3 g / m ² , dried in a standard state for 24 hours, and the coating film was observed with a scanning electron microscope. Aggregation was confirmed.

(Aqueous coating solution C)
Acrylic silicone resin emulsion (solid content 50% by weight), bio gum (solid content 100% by weight), water dispersible silica sol (pH 7.6, solid content 20% by weight, average primary particle size 27 nm), solid content weight ratio 92: The mixture was mixed at 8: 125, and water was added thereto to prepare an aqueous coating solution C having a solid content of 2% by weight and a pH of 7.2. The aqueous coating liquid C was spray-coated on black paper at a coating amount (solid content) of 3 g / m ² , dried in a standard state for 24 hours, and the coating film was observed with a scanning electron microscope. Aggregation was confirmed.

(Aqueous coating solution D)
Acrylic silicon resin emulsion (solid content 50% by weight) and water-dispersible silica sol (pH 7.6, solid content 20% by weight, average primary particle size 27 nm) were mixed at a solid content weight ratio of 100: 125, and water was added thereto. In addition, an aqueous coating solution D having a solid content of 2% by weight and a pH of 6.0 was prepared using a 0.1N aqueous acetic acid solution. This aqueous coating liquid D was spray-coated on black paper at a coating amount (solid content) of 3 g / m ² , dried in a standard state for 24 hours, and the coating film was observed with a scanning electron microscope. Aggregation was confirmed.

(Aqueous coating solution E)
Acrylic silicon resin emulsion (solid content 50% by weight) and water-dispersible silica sol (pH 7.6, solid content 20% by weight, average primary particle size 27 nm) were mixed at a solid content weight ratio of 100: 125, and water was added thereto. In addition, an aqueous coating solution E having a solid content of 2% by weight and a pH of 7.2 was prepared. This aqueous coating liquid E was spray-coated on black paper at a coating amount (solid content) of 3 g / m ² , dried in a standard state for 24 hours, and the coating film was observed with a scanning electron microscope. Existence was not recognized.

(Test Example 1)
40 parts by weight of titanium oxide dispersion (solid content 70% by weight), 160 parts by weight of heavy calcium carbonate (average particle size 8 μm), 200 ml by weight of acrylic resin emulsion (solid content 50% by weight) A matte paint was prepared by uniformly mixing 270 parts by weight (diameter 200 μm), 16 parts by weight of a film-forming aid, 5 parts by weight of a thickener, and 5 parts by weight of an antifoaming agent by a conventional method. The matte paint obtained by the above method is applied to a slate plate that has been subjected to a sealer treatment in advance so that the coating amount (solid content) is 800 g / m ^2, and the standard state (temperature 23 ° C., relative humidity) (50%) for 48 hours to form a white matte coating. The specular gloss of this matte coating film was 1.6.
Further, after adding 3% by weight of carbon black dispersion (solid content 20% by weight) to the matte paint, coating was performed in the same manner to form a gray matte coating film. The specular gloss of this matte coating film was 1.9.

Each matte coating film obtained by the above method was spray-coated with the aqueous coating solution A so that the coating amount (solid content) was 3 g / m ² and dried in a standard state for 24 hours. As a result of confirming the finished state of each specimen thus obtained, no difference from the matte coating was observed in the gloss / color state and overall texture.
Next, the white specimen was exposed outdoors at an angle of 45 degrees southward in Ibaraki City, Osaka Prefecture, and the appearance after 3 months was confirmed. As a result, the change in whiteness (ΔL) in the test body to which the aqueous coating liquid A was applied was −0.8. In addition, when the same test was done about the test body which formed only the matte coating film, that (DELTA) L was -4.5.

(Test Example 2)
A test specimen was prepared in the same manner as in Test Example 1 except that the aqueous coating liquid B was used instead of the aqueous coating liquid A. When the finished state was confirmed, there was no difference from the matte coating in terms of gloss / color and overall texture. ΔL in the outdoor exposure test was −0.6.

(Test Example 3)
A test specimen was prepared in the same manner as in Test Example 1 except that the aqueous coating liquid C was used instead of the aqueous coating liquid A. When the finished state was confirmed, there was no difference from the matte coating in terms of gloss / color and overall texture. ΔL in the outdoor exposure test was −0.6.

(Test Example 4)
A test specimen was prepared in the same manner as in Test Example 1 except that the aqueous coating liquid D was used instead of the aqueous coating liquid A. When the finished state was confirmed, there was no difference from the matte coating in terms of gloss / color and overall texture. ΔL in the outdoor exposure test was −1.2.

(Test Example 5)
A test specimen was prepared in the same manner as in Test Example 1 except that the aqueous coating liquid E was used instead of the aqueous coating liquid A. When the finished state was confirmed, generation of bottom gloss and wet color was observed. ΔL in the outdoor exposure test was −0.8.

Claims (4)

A coating layer is provided on the surface of the matte coating layer in a state where the matting coating layer is visible,
The matte layer has a specular gloss (measurement angle of 60 degrees) of 20 or less,
The coating layer includes an organic resin and silica in a solid content weight ratio of 100: 80 to 100: 500,
Silica contained in the coating layer is an aggregate derived from silica sol having an average primary particle diameter of 1 to 200 nm,
The silica sol is a water-dispersible silica sol having a pH of 5.0 or more and 8.0 or less ,
The organic resin is a combination of two or more different resins,
The coating amount of the coating layer is 0.1 to 50 g / m ² in terms of solid content. The organic resin is selected from the group consisting of an acrylic resin and a urethane resin, an acrylic silicon resin and a urethane resin, an acrylic resin and an epoxy resin, an acrylic silicon resin and an epoxy resin, an acrylic resin and a biogum, and a combination of an acrylic silicon resin and a biogum. The coating layered product according to claim 1, wherein the coating layered product is at least one kind of combination . The coating film laminate according to claim 1 or 2, wherein the coating liquid forming the coating layer has a solid concentration of 10% by weight or less. In the case where the organic resin is used in combination of two different resins,
The coating film laminate according to any one of claims 1 to 3, wherein a solid content weight ratio of one of the organic resins is less than 1/9 with respect to the other resin.