JP7387165B2 - Method for forming silica coating film and inclusion body of coating liquid used therein - Google Patents

Description

The present invention relates to a method for forming a silica coating film and an enclosure for the coating liquid used therein, and relates to a method for forming a silica coating film and an enclosure for the coating liquid used therein. The present invention relates to a method for forming a silica coating film suitable for imparting gloss and abrasion resistance, and an enclosure for a coating liquid used therein.

Patent Document 1 discloses a coating liquid in which alkoxysilane and perhydropolysilazane are dissolved in dibutyl ether as a coating liquid for applying silica coating to the surface of molded products such as plastic, glass, metal, etc. It is claimed that a silica coating with excellent transparency and mechanical properties (hardness, anti-fogging properties, bending resistance) can be easily obtained using this coating liquid by leaving it or adding water without treating it at high temperatures. There is. Further, the alkoxysilane disclosed in Patent Document 1 contains a condensate of tetraethoxysilane.

On the other hand, Patent Document 2 discloses a coating liquid containing dibutyl ether and ethyl polysilicate. Patent Document 2 also states that the coating liquid can easily apply silica glass coating to the surfaces of various articles to be coated with a protective coating, such as the display of a mobile phone.

Japanese Patent Application Publication No. 2006-219583 Patent No. 6236592 Patent No. 4759774 Japanese Patent Application Publication No. 2010-222014

According to studies conducted by the present inventors, the coating liquid used in Patent Document 1, in which alkoxysilane and perhydropolysilazane are dissolved in dibutyl ether, has a problem in storage stability at room temperature. In other words, when the coating liquid is stored at room temperature for a long period of time, condensation polymerization due to the reaction of the alkoxysilane in the coating liquid with water tends to proceed due to the presence of the perhydropolysilazane component, and the liquid becomes viscous due to gelation of the components. This makes it difficult to apply the film.

On the other hand, Patent Document 2 does not disclose what kind of composition (especially molecular weight, etc.) was specifically adopted as the ethyl polysilicate. Further, Patent Document 2 recommends impregnating a base material made of microfiber with the coating liquid and sealing the same in a container made of an aluminum pack in order to facilitate the application of the coating liquid. Paragraph 0011 of Patent Document 2 states, ``This container is particularly limited as long as it protects the dibutyl ether contained in the coating liquid from air and light, and the inner surface is made of a material that does not react with dibutyl ether. "Not done..." is written. In other words, the purpose of protection by the container is solely for dibutyl ether, which is a solvent, and no consideration has been given to protecting the ethyl polysilicate component.

Moreover, it is stated that the coating liquid of Patent Document 2 can be stored at room temperature if it is impregnated into a base material in an aluminum pack. However, the aluminum pack adopted in Patent Document 2 is estimated to be a metal foil with a thickness of about several hundred μm. In other words, it is thought that moisture is blocked from the atmosphere extremely well, so as mentioned above, even if a problem occurs, it is due to gas generation resulting from the reaction between the base material and diethyl ether. . Therefore, no consideration has been given to improving the storage stability of the coating liquid itself (especially the ethyl polysilicate component) when a container form that allows air contact to occur, such as a bottle with a cap, is used or when the coating liquid is not impregnated into the base material. do not have.

Further, Patent Document 2 only discloses a method of applying water as a fixer to the coating film as a method for converting the coating film of the coating liquid into a hard silica coating film. In this case, fixing treatment by water application contributes to ensuring film hardness, but what is required of the silica coating film is not only hardness, but also uniformity of coating, workability, appearance, speed of curing process, and is required to have durability when used for a long period of time. However, in Patent Document 2, it cannot be said that these items have been sufficiently investigated, and as mentioned above, the specific content of the ethyl polysilicate is not disclosed, so the durability of the coating and It is also not possible to estimate performance in terms of homogeneity, workability during coating, etc.

The object of the present invention is to use a method for forming a silica coating film to ensure a higher level of homogeneity and durability of the coating film, and to improve the long-term storage stability of the coating liquid at room temperature even in a simple packaging form. Another object of the present invention is to provide an encapsulated body for a coating liquid that can be suitably used in the method for forming a silica coating film.

In order to solve the above problems, the method for forming a silica coating film of the present invention uses, as a coating liquid, an organosilicon compound in which the content ratio of a partial condensate of ethyl silicate having an average molecular weight of 270 to 2000 is 80% by mass or more. The content of the main film component in the coating liquid is A (mass%), the content of the tetraethoxysilane monomer contained in the main film component in the coating liquid is B (mass%), and the main film component is The content of the dissolving or dispersible hydrophobic organic solvent in the coating liquid is C (mass%),
5≦A≦100 (mass%)
90≦A+C≦100 (mass%)
B≦90 (mass%)
40≦B+C (mass%)
a coating liquid preparation step of preparing a coating liquid in which the content of perhydropolysilazane in the coating liquid is 2% by mass or less; and an impregnation consisting of a flexible fiber aggregate or porous resin. A film of the coating liquid can be formed by impregnating a holder with the coating liquid and applying it to the surface of the object to be coated, by spraying the coating liquid onto the surface of the object to be coated, or by dipping the object to be coated in the coating liquid. A coating film forming step in which a coating film is formed on the surface of the object to be coated, and a coating film of a coating liquid is brought into contact with water to cause crosslinking and condensation polymerization while hydrolyzing a partial condensate of ethyl silicate contained in the coating liquid. , a crosslinking condensation polymerization step of converting a coating film of a coating liquid into a silica coating film.

Further, the inclusion body of the coating liquid of the present invention is used in the method for forming a silica coating film of the present invention, and the content ratio of the partial condensate of ethyl silicate having an average molecular weight of 270 to 2000 is 80% by mass. % or more of the film main component in the coating solution is A (mass %), and the content of the tetraethoxysilane monomer contained in the film main component in the coating solution is B (mass %). ), the content in the coating liquid of a hydrophobic organic solvent capable of dissolving or dispersing the main coating component is C (% by mass),
5≦A≦100 (mass%)
90≦A+C≦100 (mass%)
B≦90 (mass%)
40≦B+C (mass%)
A coating liquid prepared in such a manner that the content of perhydropolysilazane in the coating liquid is 2% by mass or less, and the coating liquid are sealed in a state that prevents moisture from penetrating into the coating liquid from the outside. The present invention is characterized by comprising a moisture-blocking sealed container.

In the present invention, by determining the content of the highly fluid and low viscosity tetraethoxysilane monomer and the hydrophobic organic solvent in the coating liquid as described above, coating the surface of the object on which the film is to be formed can be coated. The coating spreadability during application of the liquid is extremely good, and the homogeneity and durability of the resulting coating film can be ensured at a higher level. In addition, the content of perhydropolysilazane in the coating solution should be kept at 2% by mass or less, and ethyl silicate should be added to the above content of tetraethoxysilane monomer (or tetraethoxysilane monomer and hydrophobic organic solvent). Because the low molecular weight condensate is dispersed or dissolved, the gelation of the main coating component slows down even when stored in a storage format where some moisture may enter, and the coating liquid is easily absorbed even when stored in a simple packaging format. can improve long-term storage at room temperature.

FIG. 2 is a sectional view showing an embodiment of a coating liquid enclosure in which an impregnated holder is hermetically covered with a packaging container. FIG. 2 is a plan view of FIG. 1. FIG. 2 is a transparent perspective view showing an example in which a coating liquid enclosure is configured as an aerosol enclosure. FIG. 2 is a sectional view showing an example of a water-blocking sealed container configured as a bottle with an airless pump mechanism. FIG. 2 is a schematic diagram showing an example of forming a silica coating film on a paint film. FIG. 6 is a diagram illustrating an object to be coated on which a silica coating film of the form of FIG. 5 is formed.

Embodiments of the present invention will be described in detail below.
A coating liquid having the following composition is used. First, the main coating component is used to form a silica coating film on the surface of the object to be treated, and is mainly composed of a partial condensate of ethyl silicate having an average molecular weight of 270 or more and 2000 or less. Specifically, the content of the partial condensate in the main coating component is 80% by mass or more. Here, the remainder of the coating main component other than the above partial condensate is 20% by mass or less, such as the curing aid described later or perhydropolysilazane added within the permissible content range, which is a raw material component of the silica coating film to be obtained. It is considered to be a potential ingredient. The general formula of the partial condensate is _Si (OC ₂ H ₅ ) _{2 (n+1)} , and when n=1, the monomer Si(OC ₂ H ₅ ) ₄ (orthosilicic acid (tetraethyl or tetraethoxysilane). The method for producing the partial condensate is detailed in Patent Document 3, in which a predetermined amount of water is added to the monomer of tetraethyl orthosilicate, and the hydrolysis and condensation reactions are allowed to proceed in the presence of an acidic catalyst. It can be obtained by The partial condensate is a mixture of a condensate with n=2 to 10 (particularly n=4 to 6) and a monomer, and the average molecular weight can be adjusted by changing the amount of water added. In addition, since the monomer of tetraethyl orthosilicate has the property of being easily volatile, the content of the monomer can be reduced by exposing the partial condensate obtained by hydrolysis to a reduced pressure atmosphere, such as by suctioning with an aspirator. It is possible to adjust to Conversely, by adding and mixing liquid tetraethyl orthosilicate monomer to the obtained partial condensate, the content of the monomer can be adjusted in an increasing direction. In addition, in this specification, "partial condensate of ethyl silicate" is a concept consisting of a mixture of a condensate and a monomer as described above, and as the monomer content increases or decreases, the average molecular weight as a mixture increases. Change.

If the average molecular weight of the partial condensate in the coating main component is less than 270, the content of highly volatile monomers will be excessive, and the evaporation loss of ethyl silicate in the crosslinking condensation process will increase, resulting in material waste. This leads to an insufficient thickness of the resulting silica coating film. On the other hand, if the average molecular weight of the partial condensate in the main coating component exceeds 2000, the viscosity of the coating liquid will increase excessively, which will likely cause uneven coating, and may even lead to problems such as slow curing of the coating. be. The average molecular weight of the partial condensate in the main coating component is desirably adjusted to 300 or more and 1000 or less, more preferably 400 or more and 1000 or less, and still more preferably 500 or more and 850 or less.

Further, the content of perhydropolysilazane in the main coating component is 2% by mass or less. If the content of perhydropolysilazane exceeds 2% by mass, if the coating solution is kept at room temperature for a long period of time, a polycondensation reaction due to the reaction of the alkoxysilane in the coating solution with water may occur due to the presence of the perhydropolysilazane component. The problem is that the liquid becomes viscous due to the gelation of the ingredients, making it difficult to apply the film. The content of perhydropolysilazane is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably no perhydropolysilazane is contained. .

The coating liquid needs to contain 5% by mass or more of the above-mentioned main coating component. When the main coating component is less than 5% by mass, the silica coating film becomes insufficient in thickness and becomes porous, resulting in decreased durability. In addition, the tetraethoxysilane monomer in the coating main component also has the function of imparting fluidity to the coating liquid, and by ensuring a sufficient content B, the content A of the coating main component can be 100% by mass. or that the content C of the hydrophobic organic solvent be 0% by mass. Further, the content B of the tetraethoxysilane monomer in the coating liquid is 90% by mass or less. The monomer of tetraethoxysilane has relatively high volatility, and if the content B in the coating liquid exceeds 90% by mass, the amount of monomer evaporation loss during coating or curing will increase, and the silica This results in decreased durability due to insufficient thickness of the coating film and the film becoming porous. Further, the total (B+C) of the content B of the tetraethoxysilane monomer and the content C of the hydrophobic organic solvent is 40% by mass or more. When B+C is less than 40% by mass, the fluidity of the coating liquid is impaired, and coating unevenness and film thickness non-uniformity are extremely likely to occur. Regarding the lower limit of content B of tetraethoxysilane monomer in the coating liquid, B+C must be 40% by mass, and furthermore, the average molecular weight of the partial condensate of ethyl silicate in the main coating component must be 2000 or less. On the premise that the content is 0% by mass, this is not prohibited.

As the hydrophobic organic solvent, for example, ethers such as diethyl ether, dibutyl ether, ethylene glycol monoethyl ether (Cellosolve), and ethylene glycol monoethyl ether (Ethyl Cellosolve) can be used, and dibutyl ether can be particularly preferably used. . A suitable composition of a coating liquid using dibutyl ether is, for example, one containing dibutyl ether in an amount of 30% by mass or more and 95% by mass or less, and a total content of the coating main component and dibutyl ether of 95% by mass or more and 100% by mass or less. I can give an example of what is. More preferably, the coating main component should be contained in an amount of 15% by mass or more and 65% by mass or less, and dibutyl ether should be contained in a content of 35% by mass or more and 85% by mass or less, and even more preferably, a coating main component should be contained in an amount of 30% by mass or more and 60% by mass or less. , it is preferable to contain dibutyl ether in an amount of 40% by mass or more and 70% by mass or less.

In addition, the coating liquid has a hydrophobic organic solvent content C of 10% by mass or less, and a content B of the tetraethoxysilane monomer contained in the coating main component in the coating liquid of 35% by mass or more and 90% by mass. % or less, and the content of the tetraethoxysilane condensate (i.e., n≧2 in Si _n O _n-1 (OC ₂ H ₅ ) _{2 (n+1)} ) contained in the coating main component in the coating liquid. The amount can be adjusted to 10% by mass or more. Reducing the content C of the hydrophobic organic solvent means that the content A of the main coating component increases relatively. In this case, if the content B of the tetraethoxysilane monomer in the coating liquid is ensured at 35% by mass or more and the value of B+C is 40% by mass, the content A of the main coating component will be increased. Nevertheless, the fluidity of the coating liquid can be ensured well, and it becomes possible to uniformly apply the coating liquid to the surface of the object to be coated. As a result, the thickness of the silica coating film obtained by one application and curing of the coating liquid can be significantly increased. If the content of the tetraethoxysilane condensate in the coating liquid is less than 10% by mass (or if the content B of the tetraethoxysilane monomer exceeds 90% by mass), the effect of increasing the thickness of the silica coating film will not be significant. Furthermore, if the content B of the tetraethoxysilane monomer is less than 35% by mass, the fluidity of the coating liquid may not be ensured.

In addition, in the above embodiment, if the content of the tetraethoxysilane condensate contained in the main coating component in the coating liquid is 40% by mass or more, the silica coating film may not be sufficiently cured by water application, etc. There is. In this case, by adding acetic acid to the water to be coated (the amount added is adjusted appropriately so that the pH value of the water is within the range of 2.5 or more and 3.0 or less), the silica coating film can be formed. condensation is accelerated and sufficient film hardness can be obtained.

However, with this method, the residual acetic acid odor at the coating site after water application may become a problem. This problem can be solved by including a curing aid consisting of one or more of triethoxysilane, trimethoxysilane, and triethylsilane in the main coating component, so that the silica coating film can be cured without any problem even by water application without adding acetic acid. can proceed. In this case, the content of the curing aid in the coating liquid must be 1% by mass or more. On the other hand, if the content of the curing aid exceeds 5% by mass, the curing of the silica coating film may be hindered, and the above types of curing aids are expensive, which directly affects the manufacturing cost of the coating liquid. There's a problem. Therefore, it is desirable to set the content of the curing aid in the coating liquid in a range of 5% by mass or less.

On the other hand, if the content of the tetraethoxysilane condensate contained in the coating main component in the coating liquid is 10% by mass or more and less than 40% by mass, water coating without adding acetic acid is possible regardless of the addition of a curing aid. This allows the curing of the silica coating film to proceed without any problems. In this case, the content of the curing aid contained in the coating main component in the coating liquid can be kept at less than 1% by mass (including zero mass%).

Note that the total A+C of the content A of the coating main component and the content C of the hydrophobic organic solvent of the coating liquid is 90% by mass or more and 100% by mass or less. In other words, within a range of less than 10% by mass of the total weight of the coating liquid, components other than the main coating component and the hydrophobic organic solvent, such as the antibacterial agent disclosed in Patent Document 2, or the coating liquid applied to the surface of the treated object. The effects of the present invention may be hindered by the use of well-known surfactants and hydrophilic organic solvents (for example, alcohols such as ethanol, methanol, butanol or propanol, and ketones such as acetone or methyl ethyl ketone) for improving the spreadability of It is possible to contain it within the range that is not allowed.

The viscosity of the coating liquid is preferably adjusted to 0.1 mPa·s or more and 5.0 mPa·s or less. If the viscosity of the coating liquid is less than 0.1 mPa・s, either the content of highly volatile monomers becomes excessive or the amount of dibutyl ether used as a solvent is excessive. This leads to things. In addition, when the viscosity of the coating liquid exceeds 5.0 mPa·s, coating unevenness tends to occur. The viscosity of the coating liquid is desirably 0.3 mPa·s or more and 3.5 mPa·s or less, more preferably 1.0 mPa·s or more and 3.0 mPa·s or less.

The main coating component of the coating liquid preferably has an ethylsilicate monomer (tetraethyl orthosilicate monomer) content of 5% by mass or more. If the content of ethyl silicate monomer in the coating main component is less than 5% by mass, the viscosity will tend to increase rapidly due to gelation of the coating solution during the coating process, causing problems such as uneven coating. It may be more likely to occur.

The coating liquid as described above is sealed in a moisture-blocking sealed container that is sealed while preventing moisture from penetrating into the coating liquid from the outside, thereby forming the coating liquid enclosure of the present invention. 1 and 2 show an example of an enclosure for coating liquid. The liquid-impregnated body 1 is formed by impregnating an impregnated holding body 3 made of a flexible fiber aggregate or porous resin with the coating liquid. The moisture-barrier sealed container is made of a flexible sheet 2LF including an aluminum layer, and is formed as a packaging container 2 that seals and covers a liquid-impregnated body 4. If this flexible sheet 2LF is made of aluminum foil, the packaging container 2 can be configured as an aluminum pack similar to Patent Document 2.

The material of the fiber aggregate or porous resin forming the impregnated holding body 3 is, for example, in the case of fibers, aramid fibers, glass fibers, cellulose fibers, nylon fibers, vinylon fibers, polyester fibers, polyolefin fibers, rayon fibers, polyester fibers, Polyethylene fibers, rayon fibers, acrylic fibers, vinylon fibers, etc. can be listed, and the fiber aggregate can be constructed as a nonwoven fabric made of one or more of these fibers. Further, the material of the porous resin can be, for example, polyurethane.

However, the material of the impregnated holder 3 is not limited to these, as long as it does not have excessive solubility or swelling property in dibutyl ether. For example, in Patent Document 2, when the impregnated holder is made of a nonwoven fabric (microfiber) made of nylon fiber alone, the reaction with dibutyl ether is promoted, and the vapor of the reaction product is released inside the packaging container. It is mentioned that this can cause problems such as swelling. However, in the present invention, by employing a partial condensate of ethyl silicate having an average molecular weight of 270 or more and 2000 or less as the main coating component of the coating liquid, when the impregnated holder is composed of nylon fiber alone. It has been confirmed that such problems do not occur in the impregnated holder 3, and the options for the material of the impregnated holder 3 are clearly expanded.

In FIGS. 1 and 2, a flexible sheet 2LF constituting a packaging container includes an aluminum vapor-deposited layer 2M as an aluminum layer laminated by vapor deposition on a base resin layer 2B, and a base resin for the aluminum vapor-deposited layer 2M. The aluminum laminate sheet 2LF includes a heat setting layer 2S made of polyethylene resin or nylon resin and laminated on the opposite side to the layer 2B. The base resin layer can be made of polyethylene terephthalate (PET) resin, for example. The packaging container 2 has an aluminum laminate sheet 2LF that forms a sealed space for the liquid-impregnated body 3, and a bonding part that spatially closes and connects the edges of the main body 5 by thermally welding the heat setting layer 2S. 6. The thickness of the aluminum vapor deposited layer 2M is, for example, 3 μm or more and 15 μm or less, the thickness of the heat setting layer 2S is, for example, 15 μm or more and 60 μm or less, and the thickness of the base resin layer 2B is, for example, 8 μm or more and 60 μm or less.

Here, both the base resin layer 2B and the heat setting layer 2S have a certain degree of permeability to water vapor. Further, unlike aluminum foil or the like, the aluminum vapor deposited layer 2M is formed into a thin film, and therefore has many pinholes that serve as passages for water vapor. Therefore, the aluminum laminate sheet 2LF has inferior moisture barrier properties compared to aluminum foil or the like constituting the aluminum pack disclosed in Patent Document 2. However, in the present invention, by employing a partial condensate of ethyl silicate having an average molecular weight of 270 to 2000 as the main film component of the coating liquid, when the inclusion body 1 is stored at room temperature for a long period of time, Also, the problem that the liquid becomes viscous due to gelation of the components of the coating liquid and makes it difficult to apply the film is less likely to occur.

Second, the moisture-barrier sealed container can also be configured as a bottle. The material of the bottle is, for example, metal such as steel or aluminum, glass, or hard resin such as nylon. For example, the bottle may have a general structure in which the opening is closed with a cap. In this case, when using the coating liquid inside the bottle, it is necessary to open and close the cap each time, and as the coating liquid is consumed, air containing water vapor enters the bottle. The air remains above the liquid level. This water vapor in the air may accelerate the polycondensation reaction of the main film component of the coating liquid, but the coating liquid used in the present invention contains the main film component in dibutyl ether, which has extremely low solubility in water. Since a partial condensate of ethyl silicate is dispersed or dissolved in a relatively low molecular weight state, the gelation of the coating main component is slow even when stored in a manner that allows some moisture to enter. Even the simple packaging form of a bottle has the advantage of improving the long-term storage stability of the coating liquid at room temperature.

Also, as shown in FIG. 3, the coating liquid 302 can be configured as an aerosol enclosure 300 that is press-fitted into a bottle 301 along with a pressurized atomizing gas 303 consisting of an inert gas (eg, nitrogen or argon). As a result, even if the remaining amount of the coating liquid 302 in the bottle 301 decreases, it is not exposed to the atmosphere containing water vapor, so that the long-term storage stability at room temperature is significantly improved even after the start of use.

In the aerosol enclosure 300, a coating liquid 302 is enclosed in a metal bottle 301 together with a pressurized atomizing gas 303. Specifically, a mountain cup 308 in which a well-known valve unit 306 is airtightly integrated is assembled into the opening of the top 305 of the bottle 301, and a dip tube 304 is inserted downward into the container from the lower end of the valve unit 306. The lower end side is immersed in the coating liquid 302 that is the content. When the nozzle 307 attached to the valve unit 306 is pressed down, the valve opens, and while the injection gas that pressurizes the coating liquid 302 also flows into the valve unit 306, the coating liquid 302 sucked up by the dip tube 304 is pressurized from the nozzle 307. Injected with pressurized atomizing gas.

On the other hand, the moisture-blocking sealed container can also be configured as a bottle with an airless pump mechanism. By using a bottle with an airless pump mechanism, the coating liquid 302 in the bottle is not exposed to the atmosphere containing water vapor even if the remaining amount decreases, so long-term storage at room temperature is significantly improved even after the start of use.

FIG. 4 shows an example of a bottle with such an airless pump mechanism. This configuration is a well-known one disclosed in Patent Document 4 as FIG. 1. Here, only the operation thereof will be referred to from the description in Patent Document 4, and the configuration will be given the same reference numerals as in Patent Document 4, and detailed explanation will be omitted. When the user presses the pressurized discharge part 140, the pressurized discharge part 140 slides downward along the inner peripheral surface 125 of the guide cylinder part 121 of the lid 120. At this time, since the elastic restoration cap 150 is pressurized by the pressurized discharge part 140, its outer diameter is bent into an arc shape, and the pressure of the liquid in the discharge preparation chamber B increases. On the other hand, in the accommodation space 111, the space above the storage part D is in a sealed state, so when the liquid material 112 is pressurized, the air pressure in this space increases, and the liquid level of the liquid material 112 in the storage part D is increased. apply pressure to. As a result, the liquid substance 112 flows into the holding chamber C of the discharge restriction cap 130 through the outflow pipe 166. The liquid material 112 that has flowed into the holding chamber C enters the discharge preparation chamber B of the elastic restoration cap 150 through the first cut hole 133 of the discharge amount limiting cap 130 due to its pressure. Then, when the pressure in the ejection preparation chamber B increases, the second incision hole 159 opens, and the ejected liquid is ejected to the outside from the tip ejection port 143 of the pressurized ejection part 140, and is supplied to the user's desired area.

When the user releases the pressurized discharge section 140, the pressurized discharge section 140 returns to its initial state due to the elastic force of the elastic restoring cap 150. At this time, the first incision hole 133 is finally opened, the second incision hole 159 is closed, and a predetermined liquid material is stored in the discharge preparation chamber B. When the liquid substance 112 (coating liquid) in the container (bottle) 110 is supplied to the user, the pressure in the space above the reservoir D of the accommodation space 111 becomes higher than the air pressure depending on the amount of liquid substance 112 flowing out. descend. As a result, the piston 115 moves upward, and air flows into the cylinder chamber F of the container 110 from the air communication hole 114. Therefore, the amount of liquid material 112 desired by the user can be used depending on the number of times the user presses the pressurized discharge part 120. Further, as the liquid substance 112 is consumed, the piston 115 moves upward within the accommodation space 111.

The coating film forming step of forming a coating film of the coating liquid on the surface of the object to be coated using the above-mentioned coating liquid enclosure is carried out, for example, by one of the following three methods.
(1) An impregnated holder made of a flexible fiber aggregate or porous resin is impregnated with a coating liquid and applied to the surface of the object to be coated. It is suitable for implementation with the enclosures of FIGS. 1 and 2.
(2) Spraying the coating liquid onto the surface of the object to be coated. It is suitable for implementation with the enclosures of FIGS. 3 and 4.
(3) Dip the object to be coated in the coating liquid. For example, coating is performed by transferring a coating liquid sealed in a bottle with a cap to a dipping container, and dipping the object to be coated into the container and pulling it up. However, the application is limited to objects to be coated that have a structure that causes no problems even when immersed in a liquid. Further, although there is a drawback that the thickness of the formed coating film tends to be slightly uneven, it has the advantage that the coating film forming process itself can be carried out extremely easily.

The object to be coated is not particularly limited and basically may be of any kind, but some examples include various electronic devices having touch panels and displays, such as touch panels such as smartphones and tablet terminals. Examples include painted parts such as displays, arts and crafts, sanitary ware products such as toilet bowls, and the bodies of automobiles and railway vehicles, and gloss and wear resistance can be imparted to these by coating. In the present invention, the silica coating film formed by the above-mentioned coating liquid is particularly useful when at least the surface layer of the object to be coated is made of inorganic materials such as glass (including touch panels), earthenware/ceramics, or metal. Good adhesion and durability can be ensured. In particular, the coating main component in which the amount of perhydroxypolysilazane added is limited can be particularly suitably used for inorganic materials to be coated.

When the coating film of the coating liquid is brought into contact with moisture, the partial condensate of ethyl silicate contained in the coating liquid is hydrolyzed and undergoes crosslinking and condensation, and the coating film of the coating liquid is converted into a silica coating film ( crosslinking condensation polymerization step). In the crosslinking condensation polymerization step, for example, while drying the coating film of the coating liquid by evaporating the solvent in the air, water vapor in the air can be reacted with the main coating component.

Since the coating liquid used in the present invention is composed of a partial condensate of ethyl silicate with an average molecular weight of 270 to 2000 as the main coating component, the coating liquid is coated in a relatively low viscosity state immediately after the coating is formed. It has the characteristics that water vapor in the atmosphere quickly penetrates deep into the surface, the condensation polymerization reaction proceeds quickly, and curing is completed in a short time. As a result, there is an advantage that a silica coating film having practical hardness can be easily obtained by simply drying and curing in the atmosphere. Further, the thickness of the obtained silica coating film can be ensured to be 0.5 μm or more and 1.5 μm or less, which is sufficient to impart gloss and abrasion resistance to the above-mentioned coated object. In this case, when the coating film of the coating liquid is brought into contact with heated steam in the crosslinking condensation polymerization step, the hardness and strength of the resulting silica coating film become even better.

In the crosslinking condensation polymerization step, it is desirable to heat the coating film of the coating liquid to 40° C. or higher and 150° C. or lower (the same applies to the steam temperature when using the above-mentioned steam). If the temperature is less than 40°C, the effect of heating to promote condensation polymerization of the main coating component will not be significant, and if it is higher than 150°C, the coating will harden too quickly, making the resulting silica coating film prone to distortion and cracking. There are cases. Note that when the object to be coated is not suitable for high-temperature heating, such as precision electronic equipment such as a smartphone, the heating temperature is set within a range that does not interfere with the operation of the equipment (for example, 60° C. or lower).

Moreover, in the crosslinking condensation polymerization step, a step of applying liquid water to the coating film of the coating liquid can also be adopted. With this method, even if the gelation progresses slowly and the viscosity of the coating film has increased excessively, curing can be rapidly promoted. However, the application is limited to coated objects where there is little concern that problems will occur due to water wetting.

The type of object to be coated to which the method for forming a silica coating film of the present invention is applied is not particularly limited. In particular, when applied to vehicle bodies and associated equipment such as automobiles and railway vehicles, as shown in FIG. By forming this, it is extremely effective in maintaining the gloss of the coating film 211 and preventing dirt from adhering to it. In particular, railroad track equipment such as the signal 201, switch 202, and level crossing warning device 203 shown in Figure 6 are affected by iron-based contaminants from the tracks and wheels as trains pass, causing the appearance of the paint film to deteriorate in a short period of time. Frequent repainting is required due to damage. Therefore, if the silica coating film 212 is formed by the method of the present invention on the coating film on the parts and casings of these railway equipment, iron-based contaminants adhering to the silica coating film 212 can be easily removed by washing with water or wiping. can be removed, dramatically reducing the burden of painting maintenance.

Below, the results of various experiments conducted to confirm the effects of the present invention will be explained.
(Experiment example 1)
First, a coating liquid was prepared as follows. As starting materials, reagent-grade tetraethyl orthosilicate (tetraethoxysilane) and dibutyl ether (DBE: both manufactured by Tokyo Kasei Kogyo Co., Ltd.) were prepared. Next, in order to make the target value of n in the general formula Si _n O _n-1 (OC ₂ H ₅ ) _{2 (n+1)} of the partial condensate of ethyl silicate to be 3, 5, and 9, the necessary and sufficient amount for the condensation reaction is added. The amount of water added was calculated. Then, 1 kg of tetraethyl orthosilicate was weighed for each sample number, and the above calculated amount of water was added to 1 kg of tetraethyl orthosilicate using the method disclosed in Example 2 of Patent Document 3 (excluding No. 2). (without distilling off the monomer) to obtain a condensation polymer that would become the main component of the film. The average molecular weight of each condensation polymer obtained was measured by gel permeation chromatography. Furthermore, the content ratio of tetraethyl orthosilicate monomer in the main coating component was estimated by gas chromatography and distillation curve measurement. In addition, in the coating liquid used in this experimental example, the main coating component was entirely composed of a partial condensate (including monomers) of ethyl silicate.

Next, dibutyl ether was mixed with the obtained coating main component at various ratios to create coating liquids with various compositions shown in Table 1 (coating liquids with numbers marked with * in the table are within the scope of the present invention (indicates that it will be outside). Then, the viscosity of each coating liquid was measured using a B-type viscometer in a dry atmosphere at a liquid temperature of 20°C.

Next, a commercially available polyester fiber nonwoven fabric (product name: Sunfelon GR (manufactured by Sunfelt Co., Ltd.), thickness 1 mm, 100% polyester) was cut into a rectangular shape of 30 mm x 40 mm to prepare an impregnated holder, and each coating solution was The liquid-impregnated body 3 of FIG. 1 was created by weighing 1 g of the mixture and dropping it with a dropper. On the other hand, as the aluminum laminate sheet 2LF shown in FIG. 1, the base resin layer 2B made of PET resin has a thickness of 12 μm, the aluminum vapor deposition layer 2M has a thickness of 7 μm, and the heat setting layer 2S made of polyethylene has a thickness of 50 μm. prepared. The sheet was cut into a rectangular shape of 60 mm x 70 mm, and the two sheet pieces were stacked so that the heat setting layer 2S faced each other, and the three sides were thermocompressed to form a heat setting layer 2S with a width of 8 mm. It was then processed into a bag-like container. Then, the liquid-impregnated body 3 was inserted into the bag-shaped container, and a heat setting layer 2S was formed on the remaining side of the container and the container was sealed to obtain an encapsulated body.

Next, the surface of a rectangular copper test plate with a size of 60 mm x 70 mm and a thickness of 1 mm was polished to a mirror finish, degreased with ethanol, and dried. The enclosure of each coating liquid was opened, and the liquid impregnated body was applied to the surface of the test plate. The coating liquid was applied by spreading the coating while pressing with a load of 200 g. After coating, the test plate was left in a constant temperature and humidity chamber maintained at a temperature of 25° C. and a humidity of 70% RH for 1 hour to allow the coating film to harden by air drying. The thickness of the resulting coating film was measured using a fluorescent X-ray thickness meter, and the hardness of the coating film was also measured by subjecting it to a pencil hardness test specified in JIS K5600-5-4. In addition, the coating after drying treatment was visually checked to see if there were any uneven coatings based on its appearance such as glossy reflection, and was also touched with a fingertip to check for any abnormalities such as stickiness.

Further, a durability test of the coating was conducted using the above test plate as follows. First, the polyester fiber nonwoven fabric described above was cut into a strip having a width of 3 cm. A friction probe was prepared by wrapping this piece of nonwoven fabric around an eraser having a width of 30 mm, a length of 40 mm, a thickness of 10 mm, and a type A durometer hardness of approximately 35 so that the tip surface in the longitudinal direction was covered. The tip surface of the friction probe covered with nonwoven fabric was pressed against the coating on the surface of the test plate with a load of 500 g, and in this state, a friction treatment was performed by moving it back and forth with a motor-type drive device at a stroke length of 2 cm and a moving speed of 4 cm/s. repeated. The test results are: Excellent (◎) if the coating shows no abnormality such as peeling after 15,000 cycles, Good (〇) if it lasts up to 10,000 cycles, and Acceptable (△) if it lasts up to 5,000 cycles. ), and those that showed abnormalities such as peeling after being used less than 5,000 times were evaluated as poor (x). The above results are summarized in Table 1.

First, the coating main ingredients used in coating liquids Nos. 1 to 8 had an average molecular weight of 760 and a monomer ratio of 17% by mass. According to Table 1, sufficient hardness and durability can be obtained when coating liquids numbered 2 to 7 are used in which the amount of the main coating component is 5% by mass or more and 70% by mass or less, and the remainder is dibutyl ether. It can be seen that good results were obtained with little uneven coating. On the other hand, when coating liquid No. 1 (comparative example) in which the blending amount of the main coating component was less than 5% by mass was used, the film thickness was small and sufficient durability was not obtained due to the decrease in film density. I understand that. On the other hand, when coating liquid No. 8 (comparative example) in which the blending amount of the main coating component exceeds 70% by mass was used, the coating was not completely cured by air drying, resulting in insufficient hardness and durability. Ta.

Next, the main coating component used in the coating liquid of No. 9 (comparative example) was subjected to distillation of the monomer during the polycondensation treatment, and its content was reduced to 2% by mass. The total B+C of tetraethoxysilane monomer content B and dibutyl ether (DBE) content C is less than 40% by mass, and the hardness and durability of the film are relatively good, but coating unevenness It was found that there was a large occurrence of In addition, when coating solution No. 10 (comparative example) using a coating main component consisting only of monomers was used, the monomer evaporated significantly during drying, and a sufficient coating thickness was not obtained. I understand that.

On the other hand, in the coating liquids No. 11 and 12, the average molecular weight of the main coating component is low at 460 because the partial condensation reaction has not progressed compared to Nos. 2 to 7, but the monomer ratio is high at 30% by mass. It has become. It can be seen that in these cases as well, by blending the main coating component with dibutyl ether (hydrophobic organic solvent) within the scope of the present invention, coatings with excellent hardness and durability can be obtained. On the other hand, in the coating liquid No. 13, the average molecular weight of the main coating component was a little higher at 1300, and the viscosity was also increased. In this case, although some coating unevenness was observed in the resulting coating, it was found that the hardness and durability were sufficient. When using coating liquid No. 15 (comparative example) in which the average molecular weight of the main coating component exceeds the upper limit of the present invention, the viscosity of the liquid increases extremely when the dibutyl ether content is 50% by mass. However, the drying (hardening) did not progress at all in the above-mentioned natural drying, and no usable film was obtained. In addition, when coating liquid No. 14 (comparative example) in which the dibutyl ether content was increased to 95% by mass was used, the viscosity of the liquid was reduced and coating was possible, but the durability of the resulting film was poor. was insufficient.

(Experiment example 2)
A similar test using the same coating liquid as in Experimental Example 1 was conducted by changing the curing conditions after coating as follows. That is, an absorbent cotton sheet (60 mm x 70 mm, 2 mm thick rectangular shape) was impregnated with 4 cc of water, applied to the coating film of the coating solution, and placed in a constant temperature and humidity chamber maintained at a temperature of 25°C and a humidity of 40% RH for 30 minutes. The coating film was left for a few minutes to harden. The results in this case are shown in Table 2.

According to the results, it can be seen that when the coating liquids with the numbers corresponding to the examples of the present invention are used, the hardness and durability of the film generally tend to be improved compared to Experimental Example 1. On the other hand, when coating liquids with numbers corresponding to comparative examples are used, for example, for numbers 8 and 15, the hardness and durability of the film are improved, but the problem of coating unevenness is not solved, and the remaining comparative examples Together with the results obtained using the above coating liquid, it can be seen that a usable coating has not yet been obtained.

(Experiment example 3)
A similar test using the same coating liquid as in Experimental Example 1 was conducted by changing the curing conditions after coating as follows. That is, using a commercially available steam generator, 50° C. steam was sprayed onto the coating film of the coating liquid for 3 minutes to cure the coating film. The results in this case are shown in Table 3.

According to the results, it can be seen that when coating liquids with numbers corresponding to the examples of the present invention are used, the durability of the film tends to be further improved than in Experimental Example 2. On the other hand, when the coating liquid with the number corresponding to the comparative example was used, it can be seen that, as in Experimental Example 2, a usable coating was not obtained.

(Experiment example 4)
A test was conducted using the same coating liquid as in Experimental Example 1 and using the same curing conditions as in Experimental Example 3, but with the coating conditions changed as follows. That is, a coating liquid was prepared as an aerosol encapsulation body as shown in FIG. 3, and a coating film was formed by spraying a fixed amount for 10 seconds from a position 30 cm away from the surface of a test plate. The results in this case are shown in Table 4.

According to the results, when the coating liquid with the number corresponding to the example of the present invention is used, the thickness of the film can be further increased than in Experimental Example 3, and the hardness and durability are also well ensured. It can be seen that no problems such as unevenness have occurred. On the other hand, when the coating liquid with the number corresponding to the comparative example was used, it can be seen that, as in Experimental Example 3, a usable coating was not obtained.

(Experiment example 5)
Inclusion bodies similar to those in Experimental Example 1 were created using coating liquids of numbers 3, 5, 11, 12, 13, and 15 (comparative examples) of Experimental Example 1. In addition, the coating liquid No. 16 (comparative example) was obtained by adding 5% by mass of perhydroxypolysilazane (forming part of the main coating component) to the coating liquid No. 15 to replace part of the dibutyl ether. be. The content of the partial condensate (including the monomer) of ethyl silicate in the coating main component was 91% by mass only in the coating liquid No. 16 (comparative example) and 100% by mass in the others. Regarding the material of the impregnated holder of the liquid-impregnated body, two types were used: the same polyester nonwoven fabric (Holder A) as in Experimental Example 1, and a nylon nonwoven fabric (100% nylon: Holder B). In addition, two types of packaging containers are used: a packaging container similar to the aluminum pack of Patent Document 2, and a packaging container using the aluminum laminate sheet of Experimental Example 1. After storing these inclusion bodies for 180 days in a constant temperature and humidity chamber maintained at a temperature of 20°C and a humidity of 50% RH, the packaging containers were checked for swelling after storage, and each packaging container was opened. We checked the quality of the coating liquid on the liquid-impregnated body and the coating performance. The above results are shown in Table 5.

According to the results, it can be seen that when the coating liquids with the numbers corresponding to the examples of the present invention were used, no problems such as swelling or deterioration of the contents occurred in any of the forms of the inclusion bodies. On the other hand, when the coating liquid corresponding to the number corresponding to the comparative example is used, it can be seen that when an impregnated holder made of nylon nonwoven fabric is used, blistering occurs even when an aluminum pack is used. Furthermore, in the case of the enclosure using an aluminum laminate sheet, coating unevenness occurred in No. 15 due to deterioration of the contents. Further, when coating liquid No. 16 to which perhydroxypolysilazane was added was used, the liquid-impregnated body was hardened and coating itself was impossible.

(Experiment example 6)
Coating liquids with numbers 3, 5, 11, 12, 13, 15 (comparative examples) and 16 (comparative examples) similar to Experimental Example 5, and coating liquids with numbers 3 as numbers 17 (comparative examples), 18, and 19. Perhydroxypolysilazane was added in an amount of 5% by mass, 2% by mass, and 1% by mass, respectively, to replace a portion of dibutyl ether. The content of the partial condensate of ethyl silicate (including monomers) in the main coating component was 91% by mass in the coating liquid No. 16 (comparative example), 67% by mass in the coating liquid No. 17 (comparative example), The coating liquid No. 18 is 83% by mass, the coating liquid No. 19 is 91% by mass, and the others are 100% by mass. Using these, the inclusion body in a glass bottle with a cap (bottle volume: 150 cc, liquid volume when sealed 140 cc), the aerosol inclusion body shown in Fig. 3 (nitrogen gas filling: gas filling pressure 7 kg/cm ² , liquid volume when sealed 150 cc) ), and an enclosure in a bottle with an airless pump shown in FIG. 4 (liquid volume at the time of enclosure: 150 cc) were prepared, respectively. Each inclusion body was subjected to a 10-times coating cycle using 0.2 cc every 60 minutes for 30 days. Note that the storage temperature was 20°C and 5°C (refrigerator) when a glass bottle with a cap was used, and only 20°C for other containers. After 30 days, the viscosity of the contents did not change much and normal coating was possible; excellent (◎); the viscosity increased slightly but did not interfere with coating; good (〇). Those in which an increase in viscosity was observed and some unevenness was likely to occur during coating were evaluated as good (△), and those in which viscosity increased extremely and coating became impossible were evaluated as poor (x). The above results are shown in Table 6.

According to the results, it can be seen that when coating liquids with numbers corresponding to the examples of the present invention are used, good storage conditions of the coating liquid are maintained even in a simple enclosure using a glass bottle (naturally, Storage conditions are very good when using containers with airless pumps or aerosols). On the other hand, when the coating liquid with the number corresponding to the comparative example is used, it can be seen that if the bottle is stored in a glass bottle, deterioration of the contents is unavoidable unless the bottle is kept refrigerated.

(Experiment example 7)
A coating liquid was prepared as follows. As starting materials, a commercially available silicate oligomer containing a partial condensate of ethyl silicate (trade name: ethyl silicate 40, manufactured by Colcoat Co., Ltd.), reagent grade tetraethyl orthosilicate monomer (tetraethoxysilane), and curing were used. Triethoxysilane (which forms part of the main coating component) was prepared as an auxiliary agent. The silicate oligomer used contains 65% by mass of the condensate of ethyl silicate with the value of n of 2 or more, 30% by mass of tetraethyl orthosilicate monomer, and 5% by mass of ethanol, and has an average molecular weight of 575. . Tetraethyl orthosilicate monomer (tetraethoxysilane) and triethoxysilane were mixed with the silicate oligomer at various ratios to prepare coating liquids having various compositions shown in Table 7. The coating liquid of this experimental example did not contain dibutyl ether, which is a hydrophobic organic solvent. In addition, the content of the tetraethoxysilane monomer contained in the main coating component in the coating solution is 35% by mass or more and 90% by mass or less, and the content of the tetraethoxysilane condensate contained in the coating main component in the coating solution is 35% by mass or more and 90% by mass or less. The content is 10% by mass or more. The content of the partial condensate of ethyl silicate (including monomers) in the main coating component is 95% by mass for the coating solution No. 102, 97% by mass for the coating solution No. 103, and 99% by mass for the coating solution No. 104. %, the coating liquids numbered 109 and 110 are 95% by mass, and the others are 100% by mass.

Each coating liquid was sealed in a bottle equipped with an airless pump as shown in FIG. On the other hand, prepare a rectangular stainless steel test plate 60 mm x 70 mm in size and 1 mm thick that has been mirror-polished, degreased with ethanol, and dried, and apply the coating liquid from a bottle equipped with an airless pump to the test plate surface. A coating film was formed by spraying three times at a rate of 0.2 cc/time from a position 30 cm away. Water (water temperature 20°C) was sprayed onto this coating from a bottle with an airless pump of the same specifications three times on the test plate surface from a distance of 30cm at a rate of 0.2cc/time, and the temperature was 20°C (room temperature). The material was stored for one day in a constant temperature and humidity chamber maintained at a humidity of 50% RH for curing treatment. The thickness of the resulting coating film was measured using a fluorescent X-ray thickness meter, and the hardness of the coating film was also measured by subjecting it to a pencil hardness test specified in JIS K5600-5-4. In addition, the coating after drying treatment was visually checked to see if there were any uneven coatings based on its appearance such as glossy reflection, and was also touched with a fingertip to check for any abnormalities such as stickiness. Further, a durability test of the coating was conducted in the same manner as in Experimental Example 1 using the above test plate. The above results are shown in Table 7.

It can be seen that in all cases except for No. 105, a silica coating film having good strength was formed with a large thickness of 1.5 μm or more. On the other hand, the coating liquid No. 105 has a content of triethoxysilane condensate set to exceed 40% by mass (45.5% by mass), but does not contain triethoxysilane; The coating did not fully cure. However, as in No. 106, when a 5% acetic acid aqueous solution was sprayed instead of water, a silica coating film with acceptable strength and the same thickness could be formed. On the other hand, for numbers 101, 107, and 108, in which the content of the tetraethoxysilane condensate in the coating liquid was 10% by mass or more and less than 40% by mass, good strength was obtained by water spraying without adding triethoxysilane. It can be seen that a silica coating film having a large thickness can be formed. Regarding Nos. 102 to 104 and Nos. 109 and 110, similar tests were conducted using trimethoxysilane and triethylsilane instead of triethoxysilane as the curing aid. Similar good silica coatings were obtained.

(Experiment example 8)
Using a coating liquid with the same composition as that used in No. 102 of Experimental Example 7, the stainless steel (SUS) plate of Experimental Example 7, an aluminum plate, an acrylic plate, and a glass plate of the same size were prepared as test plates. In addition, a test plate in which a transparent acrylic coating film with a film thickness of 5 μm was formed on the stainless steel plate of Experimental Example 7 was also prepared. A silica coating film was formed on these test plates by the same method as in Experimental Example 7, and evaluation was performed. Note that the test plates on which the transparent acrylic coating was formed were subjected to coating and curing twice under the same conditions. The above results are shown in Table 8.

According to the above results, it can be seen that a silica coating film having good strength can be formed with a large thickness even on test plates made of materials other than stainless steel plates. Further, as shown in the results of numbers 201, 205, and 206, by repeating coating on the test plates on which the transparent acrylic coating was formed, a silica coating film with good strength could be formed with a larger thickness. These silica coatings are considered to be useful as protective coatings for coatings that require particularly high weather resistance, such as exterior coatings for automobiles, railroad vehicles, and aircraft.

Although the embodiments of the present invention have been described above, they are merely examples, and the present invention is not limited thereto.

1 Coating liquid enclosure 2 Packaging container 3 Impregnated holder 4 Liquid impregnated body 300 Aerosol enclosure 301 Bottle 302 Coating liquid

Claims (18)

As a coating liquid, the content in the coating liquid of a main coating component consisting of an organosilicon compound in which the content ratio of a partial condensate of ethyl silicate having an average molecular weight of 270 to 2000 is 80% by mass or more is A (mass%), The content of the tetraethoxysilane monomer contained in the coating main component in the coating liquid is B (mass%), and the content of a hydrophobic organic solvent capable of dissolving or dispersing the coating main component in the coating solution Assuming the amount as C (mass%),
5≦A≦100 (mass%)
90≦A+C≦100 (mass%)
B≦90 (mass%)
40≦B+C (mass%)
a coating liquid preparation step of preparing a coating liquid in which the content of perhydropolysilazane in the coating liquid is 2% by mass or less;
a coating film forming step of forming a coating film of the coating liquid on the surface of the object to be coated;
The coating film of the coating liquid is brought into contact with water, and the partial condensate of the ethyl silicate contained in the coating liquid is hydrolyzed and cross-linked and condensed, thereby converting the coating film of the coating liquid into a silica silica coating film. a crosslinking condensation process to convert into
A method for forming a silica coating film, the method comprising: 2. In the crosslinking condensation polymerization step, the coating film of the coating liquid is dried in the atmosphere by evaporating the hydrophobic organic solvent, while water vapor in the atmosphere is reacted with the film main component. Method of forming a silica coating film. The method for forming a silica coating film according to claim 1 or 2, wherein the coating film of the coating liquid is brought into contact with heated steam in the crosslinking condensation polymerization step. The method for forming a silica coating film according to claim 2 or 3, wherein in the crosslinking condensation polymerization step, the coating film of the coating liquid is heated to 40°C or more and 150°C or less. The method for forming a silica coating film according to claim 1, wherein in the crosslinking polycondensation step, liquid water is applied to the coating film of the coating liquid. The method for forming a silica coating film according to any one of claims 1 to 5, wherein the thickness of the silica coating film obtained in the crosslinking condensation polymerization step is 0.5 μm or more and 10 μm or less. An enclosure for a coating liquid used in the method for forming a silica coating film according to any one of claims 1 to 6,
As a coating liquid, the content in the coating liquid of a main coating component consisting of an organosilicon compound in which the content ratio of a partial condensate of ethyl silicate having an average molecular weight of 270 to 2000 is 80% by mass or more is A (mass%), The content of the tetraethoxysilane monomer contained in the coating main component in the coating liquid is B (mass%), and the content of a hydrophobic organic solvent that can dissolve or disperse the coating main component in the coating liquid. Assuming the amount as C (mass%),
5≦A≦100 (mass%)
90≦A+C≦100 (mass%)
B≦90 (mass%)
40≦B+C (mass%)
a coating liquid prepared in such a manner that the content of perhydropolysilazane in the coating liquid is 2% by mass or less;
a moisture-blocking sealed container that seals the coating liquid in a state that prevents moisture from penetrating into the coating liquid from the outside;
An inclusion body for a coating liquid, characterized by comprising: The coating liquid has an average molecular weight of a partial condensate of ethyl silicate contained in the main coating component of 300 or more and 2000 or less, and contains dibutyl ether as the hydrophobic organic solvent in an amount of 30% by mass or more and 95% by mass or less. The coating liquid encapsulation according to claim 7, wherein the total content of the coating main component and dibutyl ether is 95% by mass or more and 100% by mass or less. The coating liquid has a content C of the hydrophobic organic solvent of 10% by mass or less, and a content B of the tetraethoxysilane monomer contained in the main coating component in the coating liquid of 35% by mass or more. 9. The coating liquid inclusion body according to claim 8, wherein the content of the tetraethoxysilane condensate contained in the coating main component in the coating liquid is 90% by mass or less and 10% by mass or more. The coating liquid has a content of tetraethoxysilane condensate contained in the coating main component in the coating liquid of 10% by mass or more and less than 40% by mass, and a tetraethoxysilane condensate contained in the coating main component. The inclusion body of the coating liquid according to claim 9, wherein the content of the curing aid consisting of one or more of ethoxysilane, trimethoxysilane, and triethylsilane in the coating liquid is less than 1% by mass (including zero mass%). . The coating liquid has a content of 40% by mass or more of a tetraethoxysilane condensate contained in the main film component, and a triethoxysilane, triethoxysilane condensate contained in the main film component. 10. The encapsulated body of a coating liquid according to claim 9, wherein the content of the curing aid consisting of one or more of methoxysilane and triethylsilane in the coating liquid is 1% by mass or more and 5% by mass or less. The encapsulated body of a coating liquid according to any one of claims 7 to 11, wherein the average molecular weight of the coating main component in the coating liquid is 400 or more and 1000 or less. The encapsulated body of a coating liquid according to any one of claims 7 to 12, wherein the viscosity of the coating liquid is adjusted to 0.1 mPa·s or more and 5.0 mPa·s or less. The enclosure for a coating liquid according to any one of claims 7 to 13, wherein the moisture-blocking sealed container is a bottle made of metal, glass, or resin. 15. The coating liquid enclosure according to claim 14, wherein the coating liquid is configured as an aerosol enclosure which is pressurized into the bottle together with a pressurized atomizing gas consisting of an inert gas. 15. The coating liquid enclosure according to claim 14, wherein the moisture-blocking sealed container is configured as a bottle with an airless pump mechanism. An impregnated holding body made of a flexible fiber aggregate or porous resin is impregnated with the coating liquid to form a liquid-impregnated body, and the moisture-blocking sealed container is made of a flexible sheet containing an aluminum layer. The enclosure for a coating liquid according to any one of claims 7 to 13, which is formed as a packaging container for sealingly covering the liquid-impregnated body. The flexible sheet constituting the packaging container includes an aluminum vapor-deposited layer as the aluminum layer that is laminated on the base resin layer by vapor deposition, and an aluminum vapor-deposited layer that is laminated on the side opposite to the base resin layer with respect to the aluminum vapor-deposited layer. The packaging container is an aluminum laminate sheet having a heat setting layer made of polyethylene resin or nylon resin, and the packaging container is formed by thermally welding the heat setting layer to a main body portion forming a sealed space for the liquid-impregnated body using the aluminum laminate sheet. 18. The coating liquid enclosure according to claim 17, further comprising an adhesive portion that spatially closes and connects the edges of the main body portion.

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