JP2002301429A - Composition for coating building, coating method, and coating structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for coating a building, which can be cured at a room temperature in air without baking and is applicable to on-site coating such as brush coating or spray coating in air. SOLUTION: A perhydroxy polysilazane 100-50,000 in number average molecular weight which has no organic group and an oxidation catalyst such as palladium propionate, or additionally the particles of a photocatalyst such as titanium oxidize are mixed into an organic solvent having no OH group such as m- xylene. By adjusting the concentration as a solid content concentration of the perhydroxy polysilazane at 0.1-5 wt.%, the composition can be cured only by allowing it to stand at a room temperature in air and can be adhered simply to the surface of a substrate by on-site coating such as brush coating and spray coating in air.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition containing polysilazane, and more particularly to a composition for building coating capable of forming a tough coating film on a building wall or the like.
The present invention relates to a coating method and a coating structure formed thereby.

[0002]

2. Description of the Related Art
Examples of the composition for forming a polysilazane-containing coating film include a coating composition containing a polymetallosilazane obtained by heating and reacting a polysilazane and a metal alkoxide (JP-A-1-221466), and a heat reaction between a polysilazane and a silicon alkoxide. Coating composition containing a silicon alkoxide-added polymetallosilazane obtained by the reaction (Japanese Patent Application Laid-Open No. Hei 5-23827), and coating containing a glycidol-added polymetalosilazane obtained by heating and reacting polysilazane and glycidol. Composition (JP-A-6-122852), coating composition containing alcohol-added polymetallosilazane obtained by heating and reacting polysilazane and alcohol (JP-A-6-240208), polysilazane and various metal carboxylic acids Salt Coating composition comprising a reaction product obtained by response (JP-A 6-299118
No.), polysilazane and the general formula (CH3 COCHCOCH)
3) A coating composition containing an acetylacetonato complex-added polysilazane obtained by heating and reacting acetylacetonato complexes of various metals represented by nM [M is an n-valent metal] (Japanese Patent Application Laid-Open No. 6-306329). ) Is disclosed.

[0003] These polysilazane-containing coating compositions are excellent in heat resistance, abrasion resistance and chemical resistance, can form a coating having a high surface hardness, and can be fired at a relatively lower temperature. In particular, those containing perhydropolysilazane have the advantage that they can be cured at room temperature without firing.

[0004] However, in the case of a coating composition in which an oxidation catalyst such as a metal carboxylate or an acetylacetonate complex is blended with perhydropolysilazane, it can be cured at room temperature without firing as described above, Is very high, so if painting on site, that is, brushing or spraying at room temperature and air atmosphere, reacts violently with moisture and oxygen in the atmosphere, and in the case of spray coating, the spray gun body However, there was a problem that clogging occurred in a short time, and as a result, the painting operation could not be performed. In this case, it is conceivable to use a special coating system that is devised so as not to be affected by moisture or oxygen.However, using such a special coating system for on-site painting at a building site is expensive. It was not realistic.

Accordingly, a first object of the present invention is to solve the above-mentioned problems by curing at room temperature and in the air without firing, and without using a special coating system. It is an object of the present invention to provide a perhydropolysilazane-containing architectural coating composition which can be applied on site such as brush coating or spray coating.

On the other hand, in recent years, semiconductor fine particles such as titanium oxide which act as a photofunctional catalyst (hereinafter referred to as "photocatalytic particles").
And various uses such as sterilization, deodorization, declouding, and washing of these various semiconductor fine particles have been disclosed. For example, when titanium oxide is attached to the surface of a soundproof wall of a road, the outer wall of a building, a telephone box, or the like, a self-cleaning function can be given to these surfaces.

[0007] As a method of attaching such photocatalyst particles to the target surface, Japanese Patent Application Laid-Open No. 9-164091 discloses a method of supporting the photocatalyst particles on the target surface using an organic binder, And a method in which photocatalyst particles are coated on a heated plastic target surface and pressed with a mold or the like to embed the photocatalyst particles.

However, the method using an organic binder is as follows.
Due to the photocatalytic action, the organic binder around the photocatalyst particles is decomposed and loses the binder function, so that the photocatalyst falls off the substrate, so that the life is short. Also, 6
Since it was practically impossible to apply the method of baking at around 00 ° C. to the wall surface of the building, and the method of burying the photocatalyst particles described above requires that the target surface be heated in advance, Construction on the wall of the object was practically difficult.

Accordingly, a second object of the present invention is to solve the above-mentioned problems by allowing photocatalyst particles to adhere to the surface of an object without using an organic binder and without firing. An object of the present invention is to provide a polysilazane-containing architectural coating composition capable of forming a tough and long-life photocatalytically active coating on the wall surface of an object by in-situ coating.

[0010]

Means for Solving the Problems In order to achieve this object,
The present inventors first tried spray coating in the atmosphere by diluting a coating film forming composition obtained by blending perhydropolysilazane and an oxidation catalyst with an organic solvent to a limit that can be assumed as a normal coating material. The spray gun body was clogged. After that, I tried it by changing the composition such as adding various additives, but I was able to cure at room temperature and air, and I could not obtain the result that I could easily perform on-site painting in the air Was. However, a composition that was accidentally thinned to the extent that it could not be assumed as a normal paint was completed, and as a result of trying this, it was incredible that it could be cured at room temperature and in the air, and it could be easily applied in-situ in air. Have found that you can do that. The present invention has been made based on such findings.

That is, the invention of claim 1 is an architectural coating composition containing an organic solvent having no OH unit, polysilazane and an oxidation catalyst, wherein the polysilazane is a perhydropolysilazane having no organic group. (Number average molecular weight of 100 to 50,000) in a composition of 0.1 to 5% by weight in terms of solid content concentration. And photocatalyst particles are blended into the composition. Further, the invention of claim 3 is a coating method characterized in that the composition for building coating is applied by coating such as brush, roller brush, spray or the like, and the invention of claim 4 is the coating method for building coating. It is a coating structure formed by applying an object to a thickness of 0.01 μm to 1 μm.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

The architectural coating composition of the present invention can be produced by blending "polysilazane" and "oxidation catalyst" with "solvent" to prepare a polysilazane solution, and further diluting the solution with "solvent". it can. Hereinafter, the production method will be described, but the production method of the architectural coating composition of the present invention is not limited thereto, and the composition can be diluted to a predetermined concentration at once without using the “solvent”.

The "polysilazane" used in the present invention is a perhydropolysilazane in which R1, R2 and R3 are all hydrogen atoms in the following chemical formula representing polysilazane. Since perhydropolysilazane having no organic group is all H bonded to Si or N,
Not only does steric hindrance not hinder the reaction, but it is not oxidized or decomposed unlike organic groups. Therefore, at room temperature
Oxidation or hydrolysis due to water vapor in the air proceeds and cures just by holding in the air, and since it functions as a completely inorganic binder, it can form a photocatalytically active film with a long life without being decomposed by photocatalysis. it can. The molecular weight of perhydropolysilazane is not particularly limited, and those having a number average molecular weight of 100 to 50,000 can be used.

[0015]

Embedded image

The "oxidation catalyst" used in the present invention includes:
Metal carboxylates disclosed in column [0024] of JP-A-6-299118, specifically, those represented by the general formula (RCO
O) nM [M is an n-valent metal], and the metal [M] is at least selected from the group of nickel, titanium, platinum, rhodium, cobalt, iron, ruthenium, osmium, palladium, iridium, aluminum and the like. A compound having one kind of metal or an acetylacetonato complex of various metals disclosed in column [0023] of JP-A-6-306329, specifically acetylacetone (2,4)
-Pentadione) is a complex in which an anion generated by acid dissociation from a metal atom is coordinated with a general formula (CH3 COCH)
COCH3) n M [M is an n-valent metal]. Examples of the metal [M] include nickel, platinum, palladium, aluminum, rhodium and the like. However, it is not limited to these.
The amount of the “oxidation catalyst” is such that the oxidation catalyst / polysilazane polymerization ratio is 0.000001 to 2, preferably 0.001 to 1.
1, more preferably 0.01 to 0.5.

The "solvent" used in the present invention includes aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbon solvents, halogenated hydrocarbons, aliphatic ethers, alicyclic ethers, and aromatic hydrocarbons. An organic solvent such as amines having no OH group, for example, benzene, toluene, xylene, methylene chloride, chloroform, n-hexane, ethyl ether, tetrahydrofuran, pyridine, methylpyridine and the like is used. The reason why the organic solvent having no OH group is limited in the present invention is to prevent the reaction between the solvent and polysilazane.

As the "solvent" used in the present invention, the organic solvents exemplified as the solvent, that is, organic solvents having no OH group can be suitably used.

The composition for architectural coating of the present invention is prepared by mixing the "polysilazane" and the "oxidation catalyst" with the "solvent" to prepare a polysilazane solution, and further diluting the polysilazane solution with the "solvent". At this time, the mixing ratio of "perhydropolysilazane" is 0.1 to 0.1 as a solid concentration in the solvent or the solvent.
It is adjusted to contain 5% by weight, preferably 0.1 to 3% by weight. If it exceeds 5% by weight, on-the-spot painting in the atmosphere becomes impossible immediately, and if it is less than 0.1% by weight, the function as a binder is extremely reduced. JP-A-6
No. 299118, column [0031] and JP-A-6-306.
In the column [0031] of No. 329, the solvent concentration is 0 to 90.
It is described that a good result can be obtained by adjusting the amount in the range of weight%. In addition, in the composition for architectural coating used for architectural use, the concentration of the solid component is 10
Going below the percent was usually inconceivable. However, in the present invention, by adjusting the content thereof to 5% by weight or less, the effect unique to the present invention was successfully obtained.

Further, a photocatalytic action can be imparted to the coating film by blending “photocatalytic particles” with the above composition.

The “photocatalyst particles” include titanium oxide (T
iO2), iron oxide (Fe2 O3), tungsten oxide (WO1), zinc oxide (ZnO), zinc sulfide (Zn)
S), cadmium sulfide (CdS), strontium titanate (SrTiO2), molybdenum sulfide (MoS2), and other conventionally known fine particles of a photocatalyst can be used.

The "photocatalyst particles" can be directly mixed with the above-mentioned polysilazane solution. However, in order to disperse the photocatalyst particles more uniformly, various organic materials such as m-xylene and o-xylene are separately provided from the polysilazane solution. A dispersant is mixed with a solvent, photocatalyst particles are mixed with the solvent to prepare a fine particle dispersion, and the fine particle dispersion and the polysilazane solution are mixed to prepare a building coating composition. Here, as the “dispersant”, for example, Solsperse # 3000, # 9000, # 17000 manufactured by Zeneca Corp. are exemplified,
Preferably, # 9000 and # 17000 are used.
The amount of the dispersant is 5 to 50% by weight based on the photocatalyst particles.
, And particularly preferably 10 to 30% by weight.

Hereinafter, as an example of a method of applying the building coating composition of the present invention, a method of applying the composition to an exterior wall of a building will be described.

First, although necessary, prior to coating the polysilazane, the surface to be coated is washed using a high-pressure washing machine or the like, and then the surface to be coated is completely dried and cured. dry.

Then, the composition for building coating prepared as described above is applied to the outer wall surface of the building by in-situ coating such as spray coating. It is not necessary to use a special coating system specially designed so as not to be affected by moisture or oxygen as the spraying device. However, a coating efficiency of 65% or more and an atomizing air pressure of 0.1 psi to 10 psi (0. 007-0.
If an electrostatic coating machine or a high-volume low-pressure spray that conforms to the standard of 7 kg / cm 2) is used, the coating can be performed more uniformly without clogging.

At this time, the amount of the composition for architectural coating is 0.01 μm especially when photocatalyst particles are blended.
It is preferably applied to a thickness of from m to 1 μm. Speaking of the coating thickness for architectural use, it is usually 30 μm to 50 μm, so it is usually difficult to assume, but 0.01 μm to 1 μm.
m to a coating thickness of 0.01 m
The photocatalyst particles of 1 μm can be reliably scattered on the surface of the coating film, and can be securely adhered to the outer wall surface. The material to be coated is not particularly limited, such as various metals, concrete, glass, and various plastics.

The composition for architectural coating applied in this manner is allowed to stand in air at room temperature for 1 to 3 days, whereby the oxidation of perhydropolysilazane in the composition is accelerated by an oxidation catalyst, and the composition is hardened. , Or Si-NO-based ceramics, that is, a completely inorganic dense and tough film is formed. This film is excellent in corrosion resistance, heat resistance, and abrasion resistance, has high adhesion to the target surface, and is not completely decomposed or deteriorated by a photocatalyst because the film is completely inorganic.

Further, by dispersing the photocatalyst on the surface, the photocatalyst receives light of a wavelength having energy equal to or greater than the band cap, for example, light of sunlight or an electric lamp, and has a strong reducing action on the surface by photoexcitation. Electrons and holes having a strong oxidizing action are generated, and a self-cleaning function of decomposing and removing dirt substances such as organic substances and oils attached to the surface by the redox action is exhibited. In addition, Japanese Patent No. 2756474 discloses a concept that a photocatalytic action of a photocatalyst causes the surface to be chemically adsorbed in the form of a hydroxyl group (OH −) to hydrophilize the substrate surface and impart a self-cleaning function to the surface. For example, in the case of a coating composition obtained by dispersing photocatalyst particles in a silicone coating, an organic group bonded to a silicon atom of a silicone molecule is replaced with a hydroxyl group by a photocatalytic action, whereby the target surface (in other words, the surface of the silicone coating as a binder). It is to make itself hydrophilic. In contrast, the present invention uses perhydropolysilazane having no organic group, and uses a solvent and a solvent having no OH group as a solvent, so that the surface of the coating itself is hydrophilized by photocatalysis. Patent No. 2756474
It is completely different from the idea of the issue. Incidentally, Japanese Patent No. 2756474 also discloses the use of polysilazane, but is limited to an organopolysilazane compound having an organic group. From this point, the difference between the two is clear.

[0029]

Embodiments of the present invention will be described below.

(1) Production of a composition for architectural coating: Perhydropolysilazane having no organic group (inorganic polysilazane) and palladium propionate (C 2 H 5 COO)
Pd) was dissolved in an m-xylene solution to prepare a 20 wt% polysilazane solution, which was further diluted with an m-xylene solution to obtain an architectural coating composition of each formulation (formulations 1 to 4) in Table 1 below. Manufactured.

[0031]

[Table 1]

(2) Brush Coating 100 g of the composition for forming a coating film of Formulations 1 to 4 was weighed in a polycup container, and the coating amount was adjusted to 10 using a flat brush on a metal plate.
Coating was performed at a rate of ２０20 g / m 2. The work was performed in an environment of 20 ° C. and 65%. At this time, the time required for the material to react with oxygen and moisture in the air and hinder the brushing work was defined as the work limit time, and the test results are shown in Table 2. Indicated.

[0033]

[Table 2]

As a result, with respect to Formulations 1 and 2, gelation had already begun in the container before the working time of 10 or 20 minutes had elapsed, and further coating work could not be performed. On the other hand, with regard to Formulations 3 and 4, no gelling of the material occurred until the end of the coating operation (about 30 minutes), and a normal coating operation without coating unevenness could be performed.

(3) Roller brush coating 100 g of the architectural coating composition of Formulations 1 to 4 is weighed in a polycup container and applied to a metal plate using a roller brush at an application rate of 10 to 20 g / m 2. went.
The work was carried out in an environment of 20 ° C. and 65%. At this time, the time required for the material to react with oxygen and moisture in the air and hinder the brushing work was defined as a work limit time, and the test results are shown in Table 3. Indicated.

[0036]

[Table 3]

As a result, with respect to Formulations 1 and 2, gelation had already begun in the container by the time the work time passed for 10 or 20 minutes, and further coating work could not be performed. On the other hand, with regard to Formulations 3 and 4, no gelling of the material occurred until the end of the coating operation (about 30 minutes), and a normal coating operation without coating unevenness could be performed.

(4) Spray coating with an air spray gun After the composition coating composition of the above-mentioned compositions 1 to 4 is spour-coated with an air spray gun for 1 minute, the process of pausing for 30 seconds is repeated to repeat the coating operation. went. The setting and coating conditions of the used air spray gun are as follows. Nozzle diameter: 0.6 mm Blowing air pressure: 3.0 kg / cm2 Air consumption: 30 l / min Blowing distance: 200 mm Paint ejection amount: 30 ml / min Moving speed: about 20 cm / min Pattern opening: 100 mm Work at 20 ° C , 65% of the environment, at this time, the number of times the material reacts with oxygen and moisture in the air and interferes with the painting work is measured, and this is used as a guide for the paintable time,
The test results are shown in Table 4.

[0039]

[Table 4]

As a result, with regard to Formulations 1 and 2, the spraying of the material became worse due to the clogging of the nozzle after coating and stopping 2 to 5 times, and the liquid could not be sprayed from the tip of the gun. It became. On the other hand, for Formulations 3 and 4, the state at the start of spraying was maintained until all of the prepared compositions disappeared (about 15 minutes).

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor, Kanji 2--12-14, Nagatacho, Chiyoda-ku, Tokyo F-term in ABC Corporation (reference) 4D075 AA01 AC47 BB92Z CA02 CA13 CA18 CA33 CA34 DB01 DB12 DB13 DC01 DC02 DC05 EA07 EB01 EB42 EB52 EB56 EC02 EC30 EC37 4J038 DL171 KA04 KA06 MA14

Claims (4)

[Claims] An architectural coating composition comprising an organic solvent having no OH unit, polysilazane and an oxidation catalyst, wherein the polysilazane is a perhydropolysilazane having no organic group (number average molecular weight of 100 to 5). (10,000) in an amount of 0.1 to 5% by weight in terms of solid content concentration. 2. The architectural coating composition according to claim 1, further comprising photocatalyst particles. 3. A coating method comprising applying the composition for architectural coating according to claim 1 or 2 by coating with a brush, a roller brush, a spray or the like. 4. A coating structure formed by applying the composition for architectural coating according to claim 1 to a thickness of 0.01 μm to 1 μm.