JPH08302239A - Transparent coating - Google Patents

Abstract

PURPOSE: To form an effective transparent protecting film having durability without changing the original hue such as of a mortar, a concrete, a stone or a brick by coating with a composition containing a flatting agent added to a transparent resin coating material. CONSTITUTION: (B) A flatting agent comprising an inorganic precipitated barium sulfate, calcium carbonate, talc, alumina, diatomaceous earth, silica, etc., or glass, a polymeric bead or a hollow bead having preferably 2-10μm particle diameter in an amount of 5-30wt.% is added to (A) a transparent resin coating material comprising a polymeric aqueous emulsion of an acrylic resin having preferably <=100nm average particle diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent finish coating method for porous inorganic building materials such as mortar, concrete, stone, brick, etc., and has an effective durability without changing the original hue of concrete, mortar, etc. The present invention relates to a transparent coating method capable of providing a protective coating having a color.

[0002]

2. Description of the Related Art Conventionally, mortar, concrete, stone materials,
In a building or the like, which is used as a finishing material as it is without applying a protective film or the like on bricks, ceramics, etc., its appearance is impaired due to discoloration caused by rainwater and contamination by pollutants in the atmosphere, which is a problem. For the purpose of protecting those buildings,
Various transparent coating methods have been developed that do not impair the appearance of the material, but in the technique of coating with a solvent-based clear coating, the base finish is darker than the original hue (hereinafter referred to as wet color) with the paint, It was difficult to satisfy the original thought of the original design because the appearance was damaged.

Further, when an aqueous synthetic resin emulsion having a relatively large particle diameter is used, the occurrence of wet color is avoided as compared with a solvent type paint, but the emulsion particles have a large particle diameter. Poor adhesion to the base,
Due to the influence of water, the coating film swells or peels off, making it difficult to satisfy the required physical properties of the coating film.

[0004]

DISCLOSURE OF THE INVENTION In the present invention, as a result of intensive studies to solve the above-mentioned problems, a paint using a synthetic resin can be used for the purpose of protecting buildings and the like. The present invention provides a transparent coating method for finishing mortar, concrete, stone materials, bricks, ceramics, etc. without impairing the appearance and producing no wet color.

[0005]

[Means for Solving the Problems] That is, according to the present invention, a matting agent used as a matting material for general coating materials is added to a synthetic resin to overcome the conventional problems. Provide a way. There is no particular limitation on the matting agent, and inorganic matting agents such as barium sulfate, calcium carbonate, clay, talc, alumina, diatomaceous earth, silica, etc., glass, polymer beads, hollow beads, etc. However, the present invention is not limited to these matting agents. Further, the refractive index of the matting agent alone is preferably 2.0 or less so as not to impair the texture of the coated substrate.

In a commonly used matting agent, if the particle size is smaller than 2.0 μm, the specific surface area becomes large and the dispersion stability in the resin may be deteriorated. There is no choice but to reduce the amount. However, in order to provide the coating material of the present invention, a certain amount of the matting agent is required, and a certain amount or more of the matting agent is required to exert a sufficient effect. Further, if the particle size of the matting agent becomes large, problems such as sedimentation of the matting agent may occur. From these facts, it is preferable that the particle size of the matting agent is in the range of 2 to 10 μm. or,
A material with low hiding power is suitable so as not to impair the appearance of the base.

The amount of the matting agent added depends on the hiding power and refractive index of each matting agent, but the amount added is an important factor for causing diffuse reflection of incident light. 5.0% or more is necessary, and preferably 10 to 30
%.

As the synthetic resin, an aqueous polymer emulsion is used, in order to improve the adhesion to the substrate, which is a drawback of conventional aqueous emulsions, that is, to improve the penetration into the pores of the substrate, Emulsion particle size is 10
It is 0 nm or less, and even more preferably 80 nm or less. Aqueous polymer emulsion, acrylic,
Silicon, polyester, urethane, fluorine, synthetic rubber, olefins, and the like can be used, but acrylic emulsions are preferable in consideration of dispersibility, ease of handling viscosity adjustment, and suitability as a paint.

As the coating method, in addition to the single coating method of the developed product, a clear coating of the developed product, a method of using another fine particle emulsion as an undercoating agent, or a current undercoating agent can be used. However, in order to prevent a wet color from being generated as the undercoat, it is preferable to use an aqueous undercoat. In addition, it is also possible to use a silane-based penetrating water absorption inhibitor or the like as the undercoating agent.

Further, from the viewpoint of surface protection as a coating material, in order to further improve resistance such as weather resistance and stain resistance in the case of outdoor use, a general top coat agent is applied after coating the developed product. It is also possible to use and to coat two layers. Examples of the top coat agent include acrylics, silicones, polyesters, urethanes, fluorine, synthetic rubbers and olefins. However, the paint must be clear or matting paint. In addition, by combining with an undercoating agent, a three-layer coating method by overcoating the undercoating agent, the product of the present invention, and the overcoating agent is also possible.

[0011]

【Example】

Examples 1 to 6 Examples in which an acrylic emulsion is used as the base resin and fine silicic acid powder is used as the matting agent in the single coating of the product of the present invention. Example 7 An example in which an acrylic emulsion is used as the base resin and high-molecular-weight polymer beads are used as the matting agent in the single coating of the product of the present invention. Examples 8 to 9 Coatings using the product of the present invention as an overcoating agent, using an acrylic emulsion as a base resin, fine silicic acid powder as a matting agent, and an acrylic emulsion as an undercoating agent (Example 8) ), An example using a silane-based penetrating water absorption inhibitor (Example 9). Examples 10 to 11 A coating using the product of the present invention as an undercoating agent, using an acrylic emulsion as a base resin and fine powder of silicic acid as a matting agent, and a commercially available polyester-based two-component type solvent-based coating material as an overcoating agent. An example using (matte type) (Example 10), an example using a commercially available fluorine-based two-component type solvent-based paint (matt type) (Example 11). Examples 12 to 13 Coating using the product of the present invention as an intermediate coating agent, using acrylic emulsion as a base resin, fine powder of silicic acid as a matting agent, acrylic emulsion as a base coating agent, and commercially available as a top coating agent. Example (Example 12) using the polyester-based two-component type solvent-based paint (matte type), commercially available fluorine-based two-component type solvent-based paint (matte type)
Example using (Example 13).

The invention is illustrated by the following examples, in which all parts and percentages are by weight, unless stated otherwise.

[0013]

Example 1 An example in which a silicic acid-based fine particle matting agent having a refractive index of 1.46 and an average particle diameter of 2.0 μm was used in an amount of 10% based on the resin solid content. Blending composition Acrylic emulsion 60.0 parts (solid content 50% average particle diameter 52 nm) Matting agent (silicic acid type fine powder) 3.0 parts (refractive index 1.46 average particle diameter 2 μm) Dispersant (Poise 520 Kao) (Manufactured by Co., Ltd.) 1.0 part Antifoaming agent (manufactured by Nopco 8034 San Nopco Co., Ltd.) 0.1 part Water 45.9 parts Total 110.0 parts Paint obtained by stirring with a homo mixer with the above composition A mortar prescribed by JIS A-6910 was applied with a brush at 200 g / square meter, dried at room temperature for 7 days, and used for the test.

[0014]

Example 2 As a matting agent, silicic acid-based fine particles having a refractive index of 1.46 and an average particle size of 4.9 μ were used with respect to the resin solid content.
% Used example. A coating liquid and a test piece were prepared in the same manner as in Example 1.

[0015]

Example 3 As a matting agent, silica particles having a refractive index of 1.46 and an average particle diameter of 4.9 μm were used in an amount of 15 relative to the resin solid content.
% Used example. A coating liquid and a test piece were prepared in the same manner as in Example 1. Blending composition Acrylic emulsion 60.0 parts (solid content 50% average particle diameter 52 nm) Matting agent (silica fine powder) 4.5 parts (refractive index 1.46 average particle diameter 4.9 μm) Dispersant (poise) 520 Kao Co., Ltd. 1.5 parts Defoamer (Nopco 8034 San Nopco Co., Ltd.) 0.1 parts Water 48.9 parts Total 110.0 parts

[0016]

Example 4 Silicic acid fine particles having a refractive index of 1.46 and an average particle diameter of 4.9 μm were used as a matting agent with respect to the resin solid content.
% Used example. A coating liquid and a test piece were prepared in the same manner as in Example 1. Blending composition Acrylic emulsion 60.0 parts (solid content 50% average particle size 52 nm) Matting agent (silica fine powder) 6.0 parts (refractive index 1.46 average particle size 4.9 μm) Dispersant (poise) 520 Kao Co., Ltd. 2.0 parts Antifoam (Nopco 8034 San Nopco Co., Ltd.) 0.1 parts Water 51.9 parts Total 120.0 parts

[0017]

[Example 5] As a matting agent, fine particles of silicic acid particles having a refractive index of 1.46 and an average particle diameter of 4.9 µm were added to 25% of the resin solid content.
% Used example. A coating liquid and a test piece were prepared in the same manner as in Example 1. Blending composition Acrylic emulsion 60.0 parts (solid content 50% average particle diameter 52 nm) Matting agent (silica fine powder) 7.5 parts (refractive index 1.46 average particle diameter 4.9 μm) Dispersant (poise) 520 Kao Co., Ltd. 2.5 parts Defoamer (Nopco 8034 San Nopco Co., Ltd.) 0.1 parts Water 54.9 parts Total 125.0 parts

[0018]

[Example 6] As a matting agent, silica particles having a refractive index of 1.46 and an average particle diameter of 8.0 µm were used in an amount of 10 relative to the resin solid content.
% Used example. A coating liquid and a test piece were prepared in the same manner as in Example 1. Blending composition Acrylic emulsion 60.0 parts (solid content 50% average particle diameter 52 nm) Matting agent (silica fine powder) 3.0 parts (refractive index 1.46 average particle diameter 8.0 μm) Dispersant (poise) 520 Kao Co., Ltd. 1.0 part Antifoam (Nopco 8034 San Nopco Co., Ltd.) 0.1 part Water 45.9 parts Total 110.0 parts

[0019]

Example 7 An example of using 10% of polymer bead type fine particles having a refractive index of 1.49 and an average particle diameter of 8.0 μm as a matting agent with respect to the resin solid content. In the same manner as in Example 1, the coating liquid,
A test piece was prepared. Blend composition Acrylic emulsion 60.0 parts (solid content 50% average particle diameter 52 nm) Matting agent (polymer beads) 3.0 parts (refractive index 1.49 average particle diameter 8.0 μm) Dispersant (Poise 520 Kao ( Co., Ltd.) 1.0 part Defoamer (Nopco 8034 San Nopco Co., Ltd.) 0.1 part Water 45.9 parts Total 110.0 parts

[0020]

Example 8 An example in which an acrylic aqueous emulsion is used as a primer. 100g of commercially available acrylic water-based emulsion primer
The coating composition obtained in Example 4 was applied as a top coating composition under the same conditions as in Example 1 after being coated on a mortar substrate so that the coating composition would have a thickness of 1 / square meter and dried at room temperature for 1 day.

[0021]

Example 9 An example in which an aqueous silane-based penetrating water absorption inhibitor was used as the undercoating agent. A commercially available water-based silane-based water-absorption inhibitor was applied to the base material so that the amount was 200 g / square meter, and immediately after Example 4
A test piece was prepared under the same conditions as in Example 1, using the paint prepared in 1 above as the topcoat paint.

[0022]

Example 10 Example in which a topcoat agent was used in combination. After drying the sample obtained in Example 4 at room temperature for 1 day, a commercially available solvent-type matte coating (polyester two-component type)
Was used as an overcoating material to apply 200 g / square meter, and dried again at room temperature for 7 days to prepare a test piece.

[0023]

Example 11 Example in which a topcoat agent was used in combination. The sample obtained in Example 4 was dried at room temperature for 1 day, and then a commercially available solvent-type matting paint (fluorine-based two-component type) was used as the topcoat paint, and the coating was applied at 150 g / sq. A test piece was prepared by drying at room temperature for 7 days.

[0024]

Example 12 Example of use as an intermediate layer in a three-layer coating in which a top coating agent and a base coating agent were used in combination. The sample obtained in Example 8 was dried at room temperature for 1 day, and then the commercially available solvent-type matte coating (polyester two-component type) used in Example 10 was applied so that the coating amount was 200 g / square meter. Used as the top coating of the top three layers,
It was dried again at room temperature for 7 days to prepare a test piece.

[0025]

Example 13 Example of use as an intermediate layer in a three-layer coating in which a top coating agent and a base coating agent were used in combination. The sample obtained in Example 8 was dried at room temperature for 1 day, and then the commercially available solvent-type matting paint (fluorine-based two-component type) used in Example 11 was applied so that the coating amount was 150 g / square meter. The test piece was prepared by using it as the top coating material of the uppermost three layers and drying it again at room temperature for 7 days.

[0026]

[Comparative example]

Example in which no matting agent is used (Comparative Example 1) Explained in Comparative Examples below, parts and% are by weight unless otherwise specified.

[0027]

Comparative Example 1 An example in which no matting agent is used. A coating liquid and a test piece were prepared in the same manner as in Example 1 using only the aqueous acrylic emulsion used in Example 1.

Test Method The test methods and evaluation criteria for the paints and test pieces obtained from the examples and comparative examples are as follows. 1. Prevention of wet color generation Test method: Each coated piece obtained from the examples and comparative examples is visually compared with an uncoated piece. Evaluation Criteria O: The coated surface has the original appearance of the mortar, and no change in hue such as darkening is observed.

Δ: The coated surface is slightly blackish compared to the original appearance of the mortar, and a slight change in hue is observed. X: The painted surface has a black tint, which is different from the original hue of the mortar. 2. Concealment test method: Similar to the test method for preventing the occurrence of wet color, each coated piece is visually compared with an uncoated piece. Evaluation Criteria ◯: The hiding payability of the coating film is low, and a natural shading state of the mortar surface is obtained.

Δ: The hidden pay property of the coating film is slightly high, and it is difficult to obtain a natural shading state of the mortar surface. X: The coating film has high concealing payability, and no natural shading of the mortar surface is observed. 3. Adhesion test method: For each of the coated pieces obtained in Examples and Comparative Examples, which were left at room temperature, a coating film of 2 mm was formed based on the test method of the cross cut test specified in JIS-K5400.
It was cut into a corner and a peeling test was performed using a cellophane tape. Evaluation Criteria ◯: No peeling of the coating film is observed in the cellophane peeling test of the cross cut portion of 2 mm square.

Δ: In a cellotape peeling test of a cross cut portion of 2 mm square, the peeling of the coating film was 5% or less of the whole. X: In a cellotape peeling test of a cross cut portion of 2 mm square, peeling of the coating film was 50% or more of the whole. 4. Hot water resistance test method: Each of the coated pieces obtained in Examples and Comparative Examples was left at room temperature and immersed in warm water at 50 ° C for 24 hours. For blistering and peeling, visually compare the state immediately after the completion of warm water immersion. Regarding adhesion, for the coated piece immediately after completion of hot water immersion, the coating film was cut into 2 mm squares based on the test method of the cross-cut test specified in JIS-K5400, similarly to the test method of the normal adhesion test, and then the tape was cut. A peeling test was performed.

Evaluation Criteria: Blistering / Peeling A: No blistering or peeling phenomenon is observed on the surface of the sample after the hot water test. Δ: Puffing or peeling phenomenon is observed on 50% or less of the entire sample surface after the hot water test. Poor: Puffing or peeling phenomenon is observed on the entire surface of the sample after the hot water test. Adhesion ∘: No peeling of the coating film was observed in the cellotape peeling test of the cross cut portion of 2 mm square.

Δ: In a cellotape peeling test of a cross cut portion of 2 mm square, peeling of the coating film was 5% or less of the whole. X: In a cellotape peeling test of a cross cut portion of 2 mm square, peeling of the coating film was 50% or more of the whole. Similar to the evaluation method of the normal adhesion test, general paints 5. Adhesion after weather resistance test method: Each coated piece prepared above was lit for 60 minutes with a Ducycle Cycle Weatherometer using one sunshine carbon arc lamp and no filter.
Regarding the one that was subjected to a dew test for 500 hours in a 60-minute light-off cycle, the coating film was 2 mm square based on JIS-K5400, which is a general paint test method, and the cross-cut test method, similar to the test method for the normal adhesion test It was cut into pieces and subjected to a peeling test with cellophane tape.

Evaluation Criteria ◯: No peeling of the coating film was observed in the cellotape peeling test of the cross-cut portion of 2 mm square. (Triangle | delta): The peeling of a coating film is 5% or less of the whole in the cellophane tape peeling test of the cross-cut cut part of 2 mm square. X: In a cellotape peeling test of a cross cut portion of 2 mm square, peeling of the coating film was 50% or more of the whole. Similar to the evaluation method of the normal adhesion test, general paint 6. Paint stability test method: The state immediately after each of the above-prepared paints was compared with the state over time (after 30 days at room temperature).

Evaluation Criteria ◯: Stable with no increase in viscosity after coating and no separation or sedimentation of the coating. Δ: A slight increase in viscosity after conversion into a paint and a tendency toward separation and sedimentation of the paint are observed. X: Viscosity increase after coating, gelation phenomenon is observed, and coating separation or sedimentation occurs.

The test results of the samples obtained from the examples and comparative examples are shown in Tables 1 and 2.

[0037]

[Table 1]

[0038]

[Effects of the Invention] When a coating material containing a matting agent added to a synthetic resin is applied to a building or the like in which mortar, concrete, stone, brick, ceramic, etc. are finished as they are, no wet color is generated. Further, the protective coating film could be formed without changing the appearance of the base. In the above invention, the synthetic resin alone with the addition of the matting agent can be used as the coating material, but the effect is confirmed by using the undercoating agent and the topcoating agent as in the general construction coating material construction method. I can. In particular, when a solution (oil-based) paint was used as the topcoat, wetting did not occur and a sufficient effect was confirmed. Considering outdoors, it is preferable to use an undercoating agent and a topcoating agent together from the viewpoints of weather resistance and stain resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09D 133/00 PGA C09D 133/00 PGA

Claims (5)

[Claims] 1. A transparent coating method comprising applying a composition comprising a transparent resin coating material and a matting agent. 2. The transparent coating method according to claim 1, wherein the transparent resin coating material is a polymer aqueous emulsion of acrylic resin. 3. The transparent coating method according to claim 2, wherein the average particle diameter of the polymer aqueous emulsion of acrylic resin is 100 nm or less. 4. The transparent coating method according to claim 1, wherein the matting agent has a particle size of 2 to 10 μm. 5. The transparent coating method according to claim 1, wherein the amount of the matting agent added is 5 to 30% by weight based on the solid content of the resin used in the transparent resin coating material. .