JPS607029B2 - Manufacturing method for products with siliceous film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for manufacturing a product having a siliceous coating.

Until now, products with highly transparent siliceous films have been manufactured using aqueous solutions of silicates such as lithium silicate, potassium silicate, and sodium silicate on the surface of metal substrates, glass substrates, etc. It was manufactured by coating and drying it to form a coating film, and then applying it to form a siliceous film based on silicate on the surface of Motomura.

The siliceous film of the product thus obtained has high hardness, and when subjected to sufficient heat treatment, has high water resistance, acid resistance, and alkali resistance. However, this siliceous film has a large number of small holes (pinholes) formed in a distributed manner. This is due to the fact that the behavior of free water in silicate during heat treatment and the dehydration reaction of silicate were not fully understood, and therefore no appropriate measures could be taken. In this way, conventional products with siliceous coatings have a large number of small pores distributed in the silica coating, so during long-term use, the base material in the pores may be eroded or the small pores may erode. As a result, the transparency of the film was impaired. Furthermore, the alkali lj metal in the siliceous film gradually reacts with carbon dioxide and sulfur dioxide gas in the atmosphere, becoming a water-soluble component and migrating to the surface, where it dries and crystallizes, causing efflorescence (whitening). In order to avoid the occurrence of efforescence, a siliceous film is formed on the base material and then immersed for a short time in dilute aqueous solutions such as nitric acid, sulfuric acid, hydrochloric acid, and phosphoric acid. In this case, in order to effectively prevent the occurrence of efforescence, the concentration of the aqueous solution of these acids and the temperature of the solution must be increased.
Products having a siliceous coating therein must be immersed for a relatively long time. However, if you do this,
Since the siliceous film itself dissolves in the acid aqueous solution, a problem arose in that the strength of the siliceous film decreased. Further, when highly concentrated acids are used at high temperatures, the working environment deteriorates due to odors and the like, and problems such as pollution arise, so a huge amount of equipment is required to take countermeasures. In order to solve this problem, the inventors conducted detailed research on the behavior of free water in silicate during heat treatment, and found that
Pre-drying at a temperature below 0qo removes free water in the silicate, which causes small pores.
It was found that the formation of small pores in the siliceous film was significantly reduced. As a result of further research, we decided to use two types of silicates, namely IJ silicate and sodium silicate, and formed a first siliceous film using lithium silicate on the base material. After forming the siliceous film and subjecting it to dealkalization treatment if necessary, a second siliceous film is formed using sodium silicate on the first siliceous film, and the second siliceous film is subjected to dealkalization treatment. The treatment effectively prevents the occurrence of efflorescence without significantly deteriorating the siliceous film, and the siliceous film as a whole exhibits excellent chemical resistance and impact resistance. This is what I discovered. and,
As a result of further research, the inventors determined that lithium silicate and sodium silicate are composed of at least one of phosphates, borates, and aluminates of alkali metals belonging to Group LA of the periodic table. When the first and second siliceous films are formed using the modified lithium silicate and the modified sodium silicate, the modified lithium silicate and the modified sodium silicate are used to form first and second siliceous films. P24,
It has been found that the performance of the siliceous film is further improved due to the incorporation of B203 and AI203. As a result of further research, the inventors discovered that at least one of the first siliceous film and the second siliceous film was exposed to an acid aqueous solution and an acidic acid during water decomposition. The present inventors discovered that when dealkalization is performed using one or both of the salts present, the occurrence of efflorescence can be further prevented, and even if the resulting product is used under harsh conditions, no efflorescence will occur at all, and this invention has been completed. . That is, this invention provides the following general formula (1) (1) L
Lithium silicate represented by j20・xSte02・yH20 (where x is a positive number of 0.5 or more, y is 0 or a positive number) is dissolved, and an alkali belonging to Group La of the periodic table is used as a modifier. At least one of metal phosphate, borate and aluminate is P2Q, B203, respectively.
, S in the produced siliceous film in terms of AI203
A modified lithium silicate aqueous solution is prepared in which the modified lithium silicate aqueous solution is dissolved at a total ratio of 1 to 30 moles per 100 moles of the i02 component, and the following general formula (0) (0) N
a20.xSi02.y is a phosphate of an alkali metal belonging to Group La of the periodic table, in which sodium silicate represented by ○ (where x and y are the same as in general formula (1)) is dissolved, and as a modifier, , at least one of borate and aluminate are P2Q, B203, and Mt.20, respectively.
A step of preparing a modified sodium silicate aqueous solution dissolved in a total ratio of 1 to 30 moles per 100 moles of Si02 component in the produced siliceous film in terms of 3, and the above modified lithium silicate. After applying the aqueous solution to the surface of the base material and pre-drying it at a temperature of less than 100 oo,
Further, a step of forming a first siliceous film by performing a dawning treatment at a high temperature, and applying the above-mentioned modified sodium silicate aqueous solution on the first siliceous film and pre-drying it at a temperature of less than 100 qo. The first gist is a method for manufacturing a product having a siliceous film, which further comprises a step of forming a second siliceous film by performing a dawning treatment at a high temperature. After the formation of at least one of the siliceous films in step 2, the formed siliceous film is subjected to dealkalization treatment with at least one of an aqueous solution of an acid and an aqueous solution of a salt that exhibits acidity when dissolved in water. The second point is to carry out the following.

Next, this invention will be explained in detail.

First, the raw materials used in this invention will be explained.

Examples of the base material used in this invention include metal plates such as aluminum plates, glass plates, and cement plates.

However, the material is not limited to this, and any material may be used as long as it can withstand the heat during heat treatment. In particular, if an aluminum reflector is used as the base material and a highly transparent glass film is formed on it by the method of the present invention, the mirror surface of the reflector will be maintained for a long period of time and its durability will be significantly improved. Extremely useful. In other words, aluminum has traditionally been used as a reflector for lighting equipment such as floodlights and shades, but this material can easily be polished to a glossy surface (high reflectance), is lightweight, and can be easily molded. This is because it is easy. In this case, the reflective surface has been subjected to chemical polishing and electrolytic polishing, and then alumite treatment to maintain its mirror surface, thereby imparting corrosion resistance and toilet resistance. However,
Even so, the mirror surface was still susceptible to attack. However, when a siliceous film is formed on an aluminum reflector, the mirror surface of the reflector is maintained semi-permanently by the film. This is because aluminum is different from other metals.
This is thought to be due to the fact that the siliceous film and the aluminum reflector have good adhesion and fixation properties because they react with silicate. The modified lithium silicate aqueous solution to be applied to the above substrate has the following general formula Li20.XSj02.yH20 (where x is a positive number of 0.5 or more, and y is 0 or a positive number).
In addition to dissolving lithium silicate represented by used.

The above alkali metal phosphates used as modifiers include sodium monohydrogen phosphate, sodium dihydrogen phosphate, sodium orthophosphate, sodium pyrophosphate, sodium hexametaphosphate, potassium hydrogen phosphate, potassium dihydrogen hephosphate, Potassium orthophosphate, potassium pyrophosphate, potassium hexametaphosphate, amorphous P
24-Na20 composition, amorphous P2Q-Na20-K2
0 composition, phosphate glass, etc. The above alkali metal borates used as modifiers include:
Sodium borate (Na20/former 203), potassium borate (K20/former 203), lithium borate (Li2
0/Asahi 203), boric acid-containing glass, etc. Examples of the alkali metal aluminates used as modifiers include sodium aluminate, potassium aluminate, lithium aluminate, and aluminum-containing glass. Lithium silicate dissolved in a modified lithium silicate aqueous solution is not rich in acid-forming properties, but those with an x value of 0.5 to 3.9 degrees are sufficient to form a film with a thickness of 1 to 2. It is something that can be formed. However, the value of x is 7.5
If it exceeds this amount, the film-forming properties will be greatly impaired. As described above, although lithium silicate does not have high film-forming properties, the film formed by it has extremely high chemical resistance. That is, 0.5 at a temperature of 200°C or higher
The film formed by baking for more than 10 minutes has excellent acid resistance (10% HCI under room temperature for 6 hours) and alkali resistance (10% NaOH under Chinese temperature for 60 minutes) even if it is about 1 French thick. It is. In addition, the film formed by lithium silicate has extremely low occurrence of efforescence, and the film formed after aging of 200 qo or more can be used in a carbon dioxide gas or sulfur dioxide gas atmosphere even without dealkalization treatment. It does not change at the bottom. As described above, the film formed from lithium silicate has high chemical resistance and efforescence resistance, but is somewhat lacking in impact resistance and the like. The above-mentioned modifier imparts impact resistance to this film, as well as chemical resistance and anti-friction resistance. This further improves responsivity. Such a modified lithium silicate aqueous solution is prepared, for example, as follows. That is, it is prepared by dissolving the lithium silicate in water to form an aqueous solution, and dissolving the modifier in the aqueous solution. In this case, the amount of the modifier to be used can be selected such that the modifier is converted into P24, B203, and AI203, respectively, and the total ratio is 1 to 30 moles per 100 moles of Si02 component in the produced siliceous film. is necessary. If this total amount is less than 1 mole, the amount of modifier used will be too small and no effect will be exhibited. On the other hand, if the total amount exceeds 30 moles, the amount of modifier used will be too large and the resulting siliceous film will become soft and easily scratched, and its water resistance will deteriorate. When dissolving the modifier, heat and melt it so that the resulting modified lithium silicate aqueous solution becomes a transparent and uniform solution.
Alternatively, the modifier is made into an aqueous solution in advance and mixed with the lithium silicate aqueous solution. That is, if the modified lithium silicate aqueous solution becomes opaque, the transparency of the produced siliceous film tends to be impaired. Further, when preparing the modified lithium silicate aqueous solution in this way, it is preferable to set the concentration of the modified lithium silicate aqueous solution to ~30% by weight (hereinafter abbreviated as "%"). In other words, if the concentration exceeds 30%, the viscosity of the aqueous solution becomes too high, making the application process difficult;
This is because the paint film tends to crack or foam when baked, and if the concentration is less than 1%, it will be difficult to fully exhibit the effect. The modified sodium silicate aqueous solution to be applied on the siliceous film (first) formed by applying and competing the modified lithium silicate aqueous solution has the following general formula Na20 x Si02.
・yH20 (x is a positive number of 0.5 or more, y is 0 or a positive number)
Sodium silicate represented by is dissolved, and phosphates, borates, and aluminates of alkali metals belonging to group I of the periodic table are dissolved alone or in combination as modifiers. It will be done.

Specific examples of this modifier are the same as those for the modified lithium silicate aqueous solution. Sodium silicate dissolved in the modified sodium silicate aqueous solution has extremely high film-forming properties, particularly those with an x value of 0.5 to 3.2 degrees. The film formed by sodium silicate is subject to considerable thermal shock (350→2
It is an excellent product that does not crack even when subjected to mechanical shock (rapid cooling to 500°C) or mechanical impact. However, no matter how strongly the coating is applied, no matter how strongly it is treated with moths or dealkalized, it is prone to efflorescence.
Moreover, it lacks chemical resistance, especially alkali resistance.
The above-mentioned modifier imparts chemical resistance and efflorescence resistance to this film, and further improves thermal shock resistance and mechanical impact resistance. The preparation of the modified sodium silicate aqueous solution, the preferred amount of the modifier used, the preferred concentration of the modified sodium silicate aqueous solution, etc. are the same as in the case of the modified lithium silicate aqueous solution.

This invention utilizes a modified lithium silicate aqueous solution capable of producing a siliceous film having extremely high chemical resistance and efforescence resistance as described above, and a siliceous film having extremely high impact resistance and thermal shock resistance as described above. By using it together with a modified sodium silicate aqueous solution that can form a film, we can take advantage of the strengths of both to create a siliceous film that has extremely high impact resistance, thermal shock resistance, chemical resistance, and efforescence resistance as a whole. It is made to be generated on the base material.

Examples of aqueous acid solutions and aqueous salt solutions that exhibit acidity when dissolved in water that are used in the dealkalization treatment include the following. That is, as aqueous solutions of acids, HN03, Hi3P04, Hi2S04, HC1, Hi3
Examples include aqueous solutions of 803, 2C03, and organic acids. From the viewpoint of effectiveness, it is preferable to use an aqueous solution of HN03. In addition, aqueous solutions of salts that become acidic when water scales include nitrates such as aluminum nitrate, magnesium nitrate, calcium nitrate, zinc nitrate, barium nitrate, aluminum sulfate, magnesium sulfate, calcium sulfate,
Sulfates such as zinc sulfate, phosphates such as monobasic aluminum phosphate, monobasic calcium phosphate, monobasic magnesium phosphate, monobasic iron phosphate, monobasic copper phosphate, monobasic zinc phosphate, and calcium chloride, chloride Examples include aqueous solutions of hydrochlorides such as aluminum, magnesium chloride, ammonium chloride, and zinc chloride. From the viewpoint of effectiveness, it is particularly preferable to use an aqueous solution of nitrate, and it is particularly preferable to use an aqueous solution of aluminum nitrate. This dealkalization treatment includes spraying the siliceous film with an aqueous solution of the above acid, an aqueous solution of the above salt, or a mixed aqueous solution of both, or immersing the product having the siliceous film in the above aqueous solution. This is done by In this case, the concentration of the above aqueous solution is preferably set to 1 to 20%, although it varies depending on the type of processing agent. Although the treatment time varies depending on the type of treatment agent and the concentration of the aqueous solution, it is preferably set to 0.5 to 3 minutes. In particular, it is more preferable to dealkalize using an aqueous solution of a salt that becomes acidic when dissolved in water than to dealkalize using an aqueous acid solution. This is due to the following reason. In other words, whether using an aqueous acid solution or an aqueous salt solution, alkali metals are eluted from the siliceous film by dealkalization, and traces of the elution are formed.However, when dealkalization is performed using an aqueous salt solution, As elution traces are formed, cations such as metal ions of the salt enter from the salt aqueous solution and fill the elution traces, so that the surface condition of the siliceous film is less likely to be damaged. Next, an example of manufacturing a product having a siliceous film by the method of the present invention using the above raw materials will be described. First, an aqueous solution of modified lithium silicate is applied to a substrate. The method of application is not limited. For example, spraying, brushing, or immersing the substrate in an aqueous solution of modified lithium silicate is carried out. Next, the base material coated with the aqueous solution of modified lithium silicate was air-dried, and then loo was applied.

Pre-dry at a temperature of 0.000m.

This pre-drying is performed to remove free water in the modified lithium silicate coating and to prevent foaming during subsequent baking at high temperatures. Usually, this pre-drying is carried out at a temperature of 5000°C or more and less than 100°C.
．． It is carried out for 5 to 30 minutes. Next, the modified lithium silicate coating film is abraded at a high temperature to form a first siliceous film.

In this case, the baking is divided into two stages and is performed at a relatively low temperature (100
~200℃) followed by high temperature baking (~200℃).
If the secondary baking is carried out at a temperature of more than 0 and less than 40,000, the formation of small pores in the siliceous film can be further prevented. In other words, as a result of repeated research into the causes of the formation of a large number of small pores in a siliceous film, the inventors found that the cause was incomplete removal of free water in the silicate during drying and heat treatment. We discovered that the dehydration reaction of silicate during heat treatment was not fully understood and the heat treatment was performed under inappropriate conditions.Therefore, we next conducted differential thermal analysis (DTA) to investigate the dehydration reaction of silicate during heat treatment. ) and thermogravimetric analysis (TGA), the siliceous coatings were thermally treated (1
It was found that the formation of small pores in the siliceous film was significantly reduced when the temperature was further increased to a temperature exceeding 20,000 and below 40,000 (secondary baking) to allow a sufficient dehydration reaction. The printing process was divided into two stages. This first dawning is 0.5
From the viewpoint of effectiveness, it is preferable to carry out the treatment for about 30 minutes. The secondary baking after the first baking is done at 400o over 20,000 degrees.
It is preferable to carry out at a temperature of ◯ or below.

This secondary grading is carried out for the purpose of strengthening the silica film, and the baking time is usually selected to be 0.5 to 30 minutes in consideration of economic efficiency and the like. Next, the first siliceous film thus formed is subjected to dealkalization treatment, if necessary, with an aqueous solution of the acid or an aqueous solution of a salt that exhibits acidity when dissolved in water.

The first silica coating is made of modified lithium silicate and has high efflorescence resistance, but when dealkalized in this way, the efflorescence resistance is greatly improved. They will come to do so. Next, a modified sodium silicate aqueous solution is applied onto the first siliceous film, and a second siliceous film is formed by applying the same series of treatments from application of the modified lithium silicate aqueous solution to baking treatment. Form.

Next, the second siliceous film thus formed is subjected to dealkalization treatment, if necessary, with one or both of the aqueous acid solution or the aqueous solution of a salt that exhibits acidity when dissolved in water. give The second siliceous film is given efforescence resistance by a modifying agent, and when it is subjected to dealkalization treatment in this way, the efforescence resistance is greatly improved. Even if the resulting product is used under harsh conditions, no efforescence will occur. Since the performance of the first and second siliceous films has been greatly improved by the modifier, they are not affected at all by such dealkalization treatment. In addition, from the viewpoint of effectiveness, it is preferable that the thicknesses of the first and second siliceous films are each set to 0.1 to 2 mm.

In this way, a product can be obtained that has a siliceous film that is highly transparent, has no pinholes, and has extremely high efflorescence resistance, chemical resistance, and impact resistance.

That is, the siliceous coating of this product is pre-dried (to remove free water in the silicate, which causes pore formation) at a temperature below 10,000 ℃ prior to baking at high temperatures. , the formation of small pore distribution is prevented. The siliceous film is made up of two layers, and the surface side has a second siliceous film that has extremely high impact resistance and thermal shock resistance due to the modification agent, and also has high efflorescence resistance. The substrate side is made of a first siliceous film (formed from modified lithium silicate) which has extremely high chemical resistance and efforescence resistance due to the modifier. By taking advantage of the advantages of the first and second siliceous coatings, the siliceous coating as a whole becomes extremely rich in impact resistance, thermal shock resistance, chemical resistance, and effluorescence resistance. Therefore, there is no need to carry out a dealkalization treatment to prevent the occurrence of efforescence. In particular, when one or both of the first and second siliceous films are subjected to dealkalization treatment, the occurrence of efforescence can be further prevented.
Even if the obtained product is used under harsh conditions, no efflorescence will occur. Note that, if particularly necessary, the series of steps from the formation of the siliceous film to the dealkalization treatment as described above may be repeated.

Next, examples will be described together with comparative examples.

Examples, comparative examples An aluminum base material was prepared as a base material.

This aluminum base material is made by buffing a high-purity aluminum plate specified by JIS (manufactured by Sumitomo Light Metal Co., Ltd., AI070P, N purity of 97% or more, 100 x 100 x 1 side), and then dealkalizing it with a neutral detergent. Chemical polishing grade (phosphoric acid 80% by volume, acetic acid 5% by volume, nitric acid 15% by volume, liquid temperature 10%
After soaking in inkstone sand for 3 times at 0°C), washing with water, cleaning with 10% by volume NO, washing with water to give a mirror finish. Using this Motomura, as shown in Table 1 below, apply the silicate aqueous solution shown in the same table to the Motomura surface in the amount shown in the same table, heat treat as shown in the same table, and then apply as necessary. Accordingly, a product having a siliceous film was obtained by dealkalization treatment.

Next, the performance of the siliceous coating of the product having the siliceous coating obtained as described above was investigated.

The results are shown in Table 2. As is clear from Table 2, the performance of the siliceous coating of the products obtained in the Examples is extremely good. On the other hand, the siliceous coating of the product obtained in the comparative example had efflorescence, poor chemical resistance, cracking, and poor heat resistance and thermal shock resistance.
It turns out that neither of these is satisfactory. ShipsThe performance evaluation method shown in Table 2 was performed as follows.

'1) Appearance: The presence or absence of cracks was checked using a microscope (x100).

Color was visually observed. (2} Chemical resistance: 10%HC
Immerse three sheets of monkey paper (1 bar x 1 bar) in each of the aqueous solutions of I and 10% Na○cho, place them on the surface of the test specimen, cover with a watch glass, and leave at room temperature for 30 minutes. , washed with water, and observed with a magnifying glass (x25) for discoloration and corrosion.

Claims (1)

[Claims] 1 Lithium silicate represented by the following general formula (I) (I) Li_2O・xSiO_2・yH_2O (where x is a positive number of 0.5 or more, y is 0 or a positive number) is dissolved and at least one of alkali metal phosphates, borates, and aluminates belonging to Group 1a of the periodic table as a modifier is used to reduce SiO_2 in the produced siliceous film in terms of P_2O_5, B_2O_3, and Al_2O_3, respectively. A modified lithium silicate aqueous solution is prepared in which a total of 1 to 30 moles of lithium silicate is dissolved per 100 moles of the components, and the following general formula (II) (II) Na_2O x SiO_
Sodium silicate represented by 2.yH_2O (where x and y are the same as in general formula (I)) is dissolved, and a phosphate or borate of an alkali metal belonging to Group 1a of the periodic table is used as a modifying agent. and at least one of aluminates.
are P_2O_5, B_2O_3, Al_2 respectively.
SiO_ in the produced siliceous film in terms of O_3
A step of preparing a modified sodium silicate aqueous solution dissolved at a total ratio of 1 to 30 moles per 100 moles of the two components, and applying the above modified lithium silicate aqueous solution to the surface of the base material at 100°C. After pre-drying at a temperature of less than 100 ml, a baking treatment is performed at a higher temperature to form a first siliceous film, and the above-mentioned modified sodium silicate aqueous solution is applied on the first siliceous film. A method for manufacturing a product having a siliceous film, comprising the steps of pre-drying at a temperature below °C and then performing a baking treatment at a high temperature to form a second siliceous film. 2. The high-temperature baking treatment performed during the formation of the first and second siliceous films includes primary baking at a temperature of 100 to 200°C, and then secondary baking at a temperature exceeding 200°C and below 400°C. A method for manufacturing a product having a siliceous film according to claim 1, which is carried out by: 3 The time required for preliminary drying is selected within the range of 0.5 to 30 minutes, and the time required for primary baking and secondary baking are each selected within the range of 0.5 to 30 minutes. A method for manufacturing a product having a siliceous film according to Scope 2. 4. According to any one of claims 1 to 3, the base material is an aluminum substrate that has been subjected to degreasing treatment and then chemical polishing treatment or electrolytic polishing treatment to form a mirror surface with a reflectance of 75% or more. A method for producing a product with a siliceous film. 5 Lithium silicate represented by the following general formula (I) (I) Li_2O・xSiO_2・yH_2O (where x is a positive number of 0.5 or more, y is 0 or a positive number) is dissolved and used as a modifier. At least one of phosphates, borates, and aluminates of alkali metals belonging to Group 1a of the periodic table is generated in terms of P_2O_5, B_2O_3, and Al_2O_3, respectively, in the siliceous film, with respect to 100 moles of SiO_2 component. Prepare a modified lithium silicate aqueous solution in which the following general formula (II) (II) Na_2O x SiO_
An aqueous solution of sodium silicate represented by 2.yH_2O (where x and y are the same as in general formula (I)) is dissolved, and a phosphate of an alkali metal belonging to Group 1a of the periodic table, borium is added as a modifying agent. At least one of the acid salt and the aluminate is P_2O_5, B_2O_3,
A step of preparing a modified sodium silicate aqueous solution dissolved in a total ratio of 1 to 30 moles per 100 moles of SiO_2 component in the produced siliceous film in terms of Al_2O_3, and the above modified lithium silicate. A step of applying an aqueous solution to the surface of the base material, pre-drying it at a temperature of less than 100°C, and then performing a baking treatment at a higher temperature to form a first siliceous film; Apply the above modified sodium silicate aqueous solution and
a step of pre-drying at a temperature below ℃ and then performing a baking treatment at a higher temperature to form a second siliceous film;
After the formation of at least one of the siliceous film and after the formation of the second siliceous film, an aqueous acid solution and a salt exhibiting acidity when dissolved in water are applied to the formed siliceous film. A method for manufacturing a product having a siliceous film, comprising: performing a dealkalization treatment with at least one of an aqueous solution of 6 The high-temperature baking treatment performed during the formation of the first and second siliceous films includes primary baking at a temperature of 100 to 200°C, and then secondary baking at a temperature exceeding 200°C and below 400°C. A method for manufacturing a product having a siliceous film according to claim 5, which is carried out by: 7 The time required for pre-drying is selected within the range of 0.5 to 30 minutes, and the time required for primary baking and secondary baking are each selected within the range of 0.5 to 30 minutes. A method for manufacturing a product having a siliceous film as described in Scope 6. 8. According to any one of claims 5 to 7, the base material is an aluminum substrate obtained by degreasing an aluminum plate, followed by chemical polishing or electrolytic polishing to form a mirror surface with a reflectance of 75% or more. A method for producing a product with a siliceous film. 9. The siliceous material according to any one of claims 5 to 8, wherein the aqueous solution of acid for dealkalization treatment is an aqueous solution of nitric acid, and the aqueous solution of a salt that becomes acidic when dissolved in water is an aqueous solution of nitrate. A method for manufacturing products with a film.