KR20070081152A - An antifouling treating agent and an architecture plate treated by the agent - Google Patents

Abstract

An anti-fouling treatment agent for treating an architectural plate is provided to have many single silanol groups on the surface of fumed silica and to represent high fixing ability to surface of a substrate, thereby effectively manufacturing the architectural plate with ultra-hydrophilic film by comprising fumed silica dispersed in an aqueous solvent. An anti-fouling treatment agent comprises fumed silica dispersed in an aqueous solvent to form an ultra-hydrophilic anti-fouling film on the surface of a substrate. The aqueous solvent is a mixture of water and alcohol. The treatment agent further includes surfactant. A constructional plate has the ultra-hydrophilic anti-fouling film fabricated by applying the anti-fouling treatment agent to a plate and drying the coated plate. The constructional plate has a surface treated by applying paint to the surface, adding the anti-fouling agent to the surface as half-dried, heating and drying the treated surface.

Description

An antifouling treating agent and an architecture plate treated by the agent}

The present invention is, for example, antifouling agent used for the antifouling treatment of the surface of wood cement board, calcium silicate plate, cement (concrete) plate, metal plate, glass plate and the like by using the antifouling agent and the antifouling agent It is about processed building board.

For example, in a building plate such as an outer wall material, coating is generally applied to the surface by paint, but an antifouling agent for forming an antifouling film having a self-cleaning function is applied in order to remove contamination adhered to the surface after construction. .

As the antifouling agent of this kind, a superhydrophilic antifouling film is formed on the surface of the treatment, and when the antifouling agent is applied to the substrate surface, the superhydrophilic antifouling membrane is formed, and the surface of the substrate is contaminated. When water is added, water is absorbed into the superhydrophilic antifouling membrane, and consequently, contamination occurs and flows down with water (self-cleaning effect).

In order to form a superhydrophilic antifouling film on the surface of the substrate, an aqueous dispersion of silica fine particles (colloidal silica) has been mainly used.

For example, Patent Document 1 describes that a colloidal silicate film is formed on the surface of a coating film by applying an aqueous dispersion of colloidal silicic acid having an average particle diameter of 100 nm or less to the coating film of a synthetic resin aqueous emulsion as a method for forming an antifouling coating film.

In addition, Patent Document 2 describes a method of forming an antifouling layer by applying a liquid containing colloidal silica and an alumina / aluminum magnesium composite oxide for water resistance and alkali resistance on the surface of a coating film.

The silica fine particles impart superhydrophilicity to the treated surface of the substrate by silanol groups present on the surface.

[Patent Document 1] Japanese Unexamined Patent Publication No. 6-71219

[Patent Document 2] Japanese Unexamined Patent Publication No. 2002-338943

The silica fine particles contain a lot of vicinal silanols in which silanol groups present on the surface are close to each other, and the concentrations of silanol groups in the glass (hydrosilanol groups) involved in hydrophilicity by hydrogen bonding with each other. Is not very high, and surface activity is low, so that the fixing ability to the surface of the substrate is insufficient, and when rainwater or the like is applied, it is likely to leak out, and a continuous antifouling effect cannot be expected, and the concentration of single silanol groups is not very high. In order to obtain a high hydrophilic antifouling film, it is necessary to raise the density | concentration of the silica fine particle in an aqueous acid solution. However, if the concentration of the silica fine particles is high, there is a problem that the aqueous dispersion is high.

In addition, since the silica fine particles have a nano-level particle diameter (100 nm or less), when the surface of the substrate is coated, and the antifouling treatment is performed therefrom, the coating film is dried by expansion and contraction due to changes in absorption and moisture absorption and environmental temperature. It may be lifted up and buried in a coating film, and the antifouling effect may be lost.

The present invention provides an antifouling treatment agent, wherein the fumed silica is dispersed in an aqueous solvent as an antifouling agent for forming a superhydrophilic antifouling film by applying it to the surface of a substrate as a means for solving the conventional problems. It is preferable that the said aqueous solvent is a mixed solvent of water and alcohol, It is further more preferable that surfactant is added to the said aqueous solvent.

 In this embodiment, there is further provided a building plate on which the antifouling agent is coated on the surface and dried to form a superhydrophilic antifouling film. It is preferable that a coating material is apply | coated to the said building board surface, the said antifouling agent is apply | coated in a coating film semi-dry state, and it heat-drys. As the building plate, a wood cement board suitable for outer wall material or the like is suitable.

 〔Action〕

Fumed silica is produced by, for example, hydrolyzing silicon tetrachloride in an oxygen hydrogen salt, and the particle size of the primary particles is 7 to 40 nm, but when dispersed in an aqueous solvent, the particles are associated with each other to form a network structure. And secondary particles of several hundred nm (about 500 nm).

Even in the association state, glass silanol groups (single silane groups) are present at high concentration on the surface of the fumed silica, have high activity, and give high surface hydrophilicity to the substrate surface. In addition, the surface activity is large and associated to form a mesh structure to increase the apparent molecular weight, and the large surface activity and the appearance of the van der waals forces of the appearance coincide, resulting in greater fixability to the substrate surface On the surface of the substrate, excellent superhydrophilicity, that is, antifouling property, is maintained for a long time.

In addition, when a building plate is used as a base material, when a coating material is applied to the surface of the building plate and the antifouling agent is applied in a semi-dry state of the coating film, the antifouling agent is applied in a state in which the coating film on the surface of the base material is in a semi-cured state and has adhesiveness. Since it is applied, the fumed silica becomes slightly stuck to the coating film, and the adhesion to the coating film of the antifouling layer formed is improved. As described above, the fumed silica has a large volume by associating particles with each other, and even though it is slightly embedded in the coating film, the fumed silica does not reach the point of being buried, and even if the coating film is stretched by absorption or moisture absorption or environmental temperature change, the mixed fume is mixed. Since desilica is not buried and buried in the said coating film, antifouling property does not fall.

In the antifouling agent, when the fumed silica is dispersed in a solvent containing alcohol, water, and more preferably a surfactant, wetting of the coating film is reduced by the action of lowering the surface tension of the alcohol and the surfactant. The affinity with the coating film is improved, and the adhesion to the coating film of the antifouling layer formed is further improved. In addition, the fumed silica is uniformly dispersed by the surfactant without sedimentation.

〔effect〕

In the antifouling treatment agent of the present invention, fumed silica having a large number of single silanol groups present on the surface is used, and thus, a large antifouling effect with a high fixability to the substrate and a permanent property is exhibited.

Example

This invention is demonstrated in detail below.

(Fumed silica)

As described above, the fumed silica used in the present invention is produced by combustion hydrolysis in oxyhydrogen salt in the gas phase of volatile silicon compounds such as silicon tetrachloride.

The particle diameter of the primary particles of the fumed silica is 7 to 40 nm, but when dispersed in an aqueous solvent, the particle mutuals associate to form a mesh structure, resulting in several hundred nm (about 500 nm) secondary particles.

The specific surface area of the fumed silica is about 500,000 to 2,000,000 cm ² / g, and has 2 to 3 single silanol groups per 1 nm ^2. Therefore, the fumed silica is rich in surface activity and gives high surface hydrophilicity to the substrate surface. .

〔Alcohol〕

In this invention, it is preferable to add alcohol to water as a dispersion solvent of the said fumed silica. As alcohol used for this invention, it is preferable that it is water-soluble, such as methanol, ethanol, isopropanol. The alcohol lowers the surface tension of the antifouling treatment agent of the present invention, and also improves the affinity between the antifouling treatment agent and the underlying substrate or the coating film formed on the substrate, thereby improving the wettability of the treatment agent.

〔Surfactants〕

It is preferable to add surfactant to the antifouling agent of this invention. As the surfactant, any of conventional anionic, nonionic, and cationic surfactants can be used. For example, as the anionic surfactant, higher alcohol sulfate (Na salt or amine salt), alkylallyl sulfonate (Na salt or amine) can be used. Salts), alkylnaphthalenesulfonates (Na salts or amine salts), alkylnaphthalenesulfonates condensates, alkylphosphates, dialkylsulfosuccinates, rosin soaps, fatty acid salts (Na salts or amine salts), and the like. As surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkrolamine, polyoxyethylene alkylamide, sorbitan alkyl ester, polyoxyethylene sorbate Non-alkyl alkyl esters, and cationic surfactants include octadecylamine acetate, imidazoline derivatives, and poly The alkylene polyamine derivative or salt thereof, octadecyl trimethyl ammonium chloride, trimethyl amino Need to do with it in ethyl Need alkylamide, alkyl pyridinium sulphate, alkyl trimethylammonium can be given. Moreover, you may mix and use 2 or more types of surfactant. In addition, the said illustration does not limit this invention.

Together with the alcohol, the surfactant lowers the surface tension of the antifouling treatment agent of the present invention, disperses the fumed silica in the treatment agent well, and increases the affinity with the coating film below.

In the antifouling agent of the present invention, the fumed silica is usually 0.1 to 10% by mass, preferably 0.5 to 6% by mass, 2 to 10% by mass of alcohol, 0.01 to 0.25% by mass of surfactant, and the rest is Do it with water.

When the alcohol is contained in an amount less than 2% by mass, the wettability of the treatment agent is deteriorated, and when the alcohol is contained in an amount exceeding 10% by mass, the volatility of the solvent is increased, which adversely affects the painting work. In addition, when the said surfactant is added less than 0.01 mass%, the effect of lowering the surface tension by a surfactant and the dispersing effect of fumed silica become less remarkable, and when it exceeds 0.25 mass%, it forms. This will adversely affect the strength, water resistance and durability of the antifouling layer. In this way, it is preferable that the surface tension of the said treating agent is 20 dyne / cm or less at 25 degreeC.

The base material to which the antifouling agent of the present invention is applied is mainly a building board such as an outer wall material, and the building board mainly includes wood reinforcing materials such as wood chips, wood fiber bundles, wood pulp, wood hair, wood powder, and cement-based hydraulic materials. The wood cement board which shape-hardened the mixture made into the main body is used, and the surface may be provided with the uneven | corrugated shape 2 by embossing etc. The surface of the said board | plate material is coated. The coating is carried out using inorganic paints such as organic paints such as acrylic resin paints, acrylic-silicone paints, acrylic-urethane resin paints, phosphate paints, and metal oxide paints, but is generally used for undercoat, heavy paint and overcoat. Three-layer coating, or two-layer coating of undercoat and overcoat are applied.

As a coating material used for the said coating, it is preferable to use the aqueous emulsion paint like acrylic resin aqueous emulsion paint. This is because the coating film of the aqueous emulsion paint contains hydrophilic components such as a surfactant, and has high affinity with the aqueous antifouling agent.

In this invention, the said antifouling agent is apply | coated in the semi-dry state, ie, the semi-hardened state, the coating film formed by apply | coating paint on the surface of the said base material. In the case of 2 or 3 layer coating, the said antifouling agent is apply | coated in the semi-dry state by the overcoat.

The semi-dry state of the coating means a state before the solvent or water does not completely evaporate in the case of a coating film using a solvent-based paint or an aqueous emulsion paint. In the case of a solvent-free paint, the resin vehicle or the inorganic vehicle in the paint is completely It refers to the semi-cured state that is not cured.

Normally, the semi-dry state is realized for 10 to 60 seconds after the coating is formed. In a solvent paint or an aqueous emulsion paint, solid content concentration becomes high from 30-50 mass% to 60-80 mass% during this time.

In the semi-dry state of the coating film, the fumed silica in the antifouling agent becomes slightly stuck in the coating film, and the adhesion to the coating film of the formed antifouling layer is improved, and mixing does not occur between the formed antifouling layer and the coating film. Do not.

As a base material made into this invention other than the said building board, a calcium silicate board, a cement (concrete) board, a metal board, a glass board, etc. are mentioned, for example.

As a preferable method of apply | coating the said antifouling agent to the surface of a base material, there is a atomization coating method. Examples of the atomization coating method include a low pressure airless spray method, a coating method by a bell-type coating machine, an electrostatic coating method, and the like. As the coating method, brush coating, roll coater coating, knife coater coating, or the like may be applied.

In the said atomizing coating method, since the said processing agent becomes a mist and adheres to the uneven | corrugated surface of a building board, it is easy to settle on the said surface.

[Examples 1 to 11, Comparative Examples 1 to 3]

The components shown in Table 1 were added to water and mixed to prepare an antifouling agent.

After dispersing the fumed silica, a bead mill was used, followed by dispersion for 40 minutes with ultrasonic waves. An aqueous styrene-acrylic paint was applied to the surface of a 50 × 40 mm wood fiber mixed calcium silicate plate to prepare a substrate for confirming the antifouling effect in the present invention.

The antifouling agent of the formulation shown in Table 1 was apply | coated to the base material prepared as mentioned above so that it might become 5 g / chuck ² , and it dried at room temperature, and used for the test.

[Test 1]

The test bodies of Examples 1 to 11 and Comparative Examples 1 to 3 obtained as described above were fixed to a mount having a tilt angle of 30 ° toward the south side, and were actually exposed to the outdoors for 2 months, and the antifouling The effect was confirmed. The difference (ΔL) of lightness (L value) by the minolta color difference system CR-300 was used for evaluation of the contamination degree. The results are shown in Table 2.

[Test 2]

The test bodies of Examples 1 to 11 and Comparative Examples 1 to 3 prepared under the same conditions were washed with high pressure water for 1 minute, and the change in contact angle with the water before and after the washing was measured to confirm the hydrophilization effect. It was. The results are shown in Table 2.

[Test 3]

The test bodies of Examples 1 to 11 and Comparative Examples 3 to 3 prepared under the same conditions were immersed in water maintained at 25 ° C. for 3 days, and the change in contact angle with water was measured before and after the hydrophilization effect. It was confirmed. The results are shown in Table 2.

[Result of test 1]

Table 2 shows that ΔL of Comparative Example 1, which is untreated, is large at 6.5, and ΔL (4.1) of the test body treated with the antifouling agent of Comparative Example 2 having a colloidal silica concentration of 2% by mass is 0.5% by mass of fumed silica. Almost identical to ΔL (4.4) of the test body treated with the antifouling agent of Example 9, and ΔL (1.8) of the test body treated with the antifouling agent of Comparative Example 3 having a colloidal silica concentration of 6% by mass was fumed silica concentration 2 The same as ΔL (1.8) of the test body treated with the antifouling agent of Example 8 in mass%, and ΔL (1.6) of the test body treated with the antifouling agent of Example 3 having a fumed silica concentration of 2% by mass was Comparative Example 2 The ΔL (1.3) of the test body which was much smaller than the ΔL (4.1) of the test body and treated with the antifouling agent of Example 5 having a fumed silica concentration of 6% by mass, was smaller than the ΔL (1.8) of the test body of the comparative example 3, and the fume It is confirmed that the antifouling agent using desilica has durable antifouling properties.

[Result of test 2, 3]

The contact angle θ of Test 2 is large at 81 ° from before the cleaning in Comparative Example 1 without treatment, and slightly smaller at 72 ° after washing. In Comparative Examples 2 and 3 using colloidal silica, and Examples 1 to 11 using fumed silica, θ = 0 ° before washing, showing good hydrophilicity, but θ = 0 ° in Example 3 after washing. Compared with, θ = 45 ° in Comparative Example 2, the antifouling agent treated surface using fumed silica is better hydrophilicity after cleaning than the antifouling agent treated surface using colloidal silica, and in the test 3 compared with no treatment Example 1 shows a large value such as θ = 88 ° before immersion and θ = 70 ° after immersion, and Comparative Examples 2, 3, and 1 to 11 all have θ = 0 ° before immersion and good hydrophilicity. However, after immersion, θ = 42 ° in Comparative Example 2, θ = 0 ° in Example 3, θ = 22 ° in Comparative Example 3, and θ = 0 ° in Example 5, and the antifouling agent using colloidal silica was used. On the surface treated by the part, hydrophilicity was confirmed to fall significantly by water immersion.

The surface treated with the antifouling agent of the present invention exhibits durable antifouling properties and is useful for building materials such as exterior wall materials exposed to the outdoors.

Claims (6)

An antifouling agent applied to the surface of a substrate to form a superhydrophilic antifouling film, wherein the fume silica is dispersed in an aqueous solvent.  The antifouling agent according to claim 1, wherein the aqueous solvent is a mixed solvent of water and alcohol. The antifouling agent according to claim 1 or 2, wherein a surfactant is added to the aqueous solvent. A building plate characterized by applying the antifouling treatment agent according to claim 1 or 2 on a surface thereof and drying it to form a superhydrophilic antifouling film. 5. The building plate according to claim 4, wherein a paint is applied to the surface of the building plate, and the antifouling agent is applied and heat-dried in a semi-dry state of the film. The building plate of claim 4, wherein the dry plate is a wood cement plate.