JPS607030B2 - 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.

0 Products with highly transparent siliceous films have been produced by applying aqueous solutions of silicates such as lithium silicate, potassium silicate, and sodium silicate to the surface of base materials such as metal and glass substrates. was applied and dried to form a coating film, which was then baked to form a siliceous film based on silicate on the surface of the base material.

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 coating has a large number of pinholes distributed in it, so during long-term use, the base material in the pores may be eroded, or the pores may damage the coating. Transparency was being compromised. In addition, the alkali metals in the siliceous film gradually react with carbon dioxide and sulfite gas in the atmosphere, becoming water-soluble components and migrating to the surface, where they dry and crystallize, causing efflorescence (whitening). I was doing a lot of things. In order to avoid the occurrence of this efflorescence, after forming a siliceous film on the base material, this is immersed for a short time in a dilute aqueous solution such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc., and the alkali metal in the film is removed. is being removed. In this case, in order to effectively prevent the occurrence of efforescence, it is necessary to increase the concentration and temperature of the aqueous solution of these acids, and soak the product with a siliceous film in it for a relatively long time. There is a need. However, in this case, the siliceous film itself dissolves in the acid aqueous solution, resulting in a problem that the strength of the siliceous film decreases.
Furthermore, when acids are used, 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 deal with these problems. In order to solve these problems, the inventors conducted detailed research on the behavior of free water in silicates during heat treatment, and found that the results showed that the silicates were exposed to a dawning treatment at high temperatures. 100q prior to
It has been found that pre-drying at a temperature of less than 0.0°C significantly reduces the formation of pores in the siliceous film because free water in the silicate, which causes pores, is removed.

As a result of further research, we decided to use two types of silicates, namely sodium silicate and lithium silicate, and formed a first siliceous film with sodium silicate on the substrate. However, by forming a second siliceous film using lithium silicate on top of this, the occurrence of efflorescence can be effectively prevented without performing alkalization treatment, and the siliceous film as a whole has excellent chemical resistance. They discovered that the material also exhibits improved impact resistance and other properties. As a result of further research, the inventors discovered that sodium silicate and lithium silicate are at least one of the phosphates, borates, and aluminates of alkali metals belonging to Group LA of the periodic table. When first and second siliceous films are formed using the modified sodium silicate and modified lithium silicate, the modifier is added to the first and second siliceous films formed. P205, string 03, AI20 derived from
It has been found that the performance of the siliceous film is further improved by the incorporation of 3. As a result of further research, the inventors found that at least one of the first siliceous film and the second siliceous film,
When dealkalization is performed using either or both of an aqueous acid solution and a salt that exhibits acidity when dissolved in water, the occurrence of efflorescence is further prevented, and even when the resulting product is used under harsh conditions, there is no efflorescence. He discovered that this phenomenon no longer occurs and completed this invention. That is, this invention:
The following general formula (1) (1) Na20・xSmi02・
Sodium silicate represented by yH20 (where x is a positive number of 0.5 or more, y is 0 or a positive number) is dissolved, and a phosphate of an alkali metal belonging to Group La of the periodic table as a modifying agent, At least one of borates and aluminates is dissolved in a total ratio of 1 to 30 moles per 100 moles of Si02 component in the produced siliceous film in terms of P2Q, B203, and Niji 203, respectively. At the same time, prepare a modified sodium silicate aqueous solution containing the following general formula (b)(n) Li20・oi02・
yH20 (however, x and y are the same as in general formula (1))
Lithium silicate represented by is dissolved, and at least one of phosphate, borate, and aluminate of an alkali metal belonging to Group La of the periodic table is used as a modifier in terms of P2Q, B203, and AI203, respectively. A step of preparing a modified lithium silicate aqueous solution dissolved in a total ratio of 1 to 30 moles per 100 moles of Si02 component in the siliceous film produced by the process, Apply to the surface of
After pre-drying at a temperature of less than After pre-drying at a temperature below
The first gist is a method for manufacturing a product having a siliceous film, which comprises a step of further performing a plating treatment at a high temperature to form a second siliceous film. After the formation of at least one of the siliceous films, 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 main point is to do this.

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 siliceous 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 to impart corrosion resistance and weather resistance. However, 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 thought to be because, unlike other metals, aluminum reacts with silicates, so that the siliceous film and the aluminum reflector have good adhesion and fixation. The modified sodium silicate aqueous solution to be applied and baked on the above substrate has the following general formula Na20.xSj02.yH20 (where x is a positive number of 0.5 or more, and 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. used.

The above-mentioned alkali metal phosphates used as modifiers include sodium monohydrogen phosphate, sodium dihydrogen phosphate, sodium orthophosphate, sodium pyrophosphate, sodium hexametaphosphate to potassium hydrogen phosphate, and dihydrogen phosphate. potassium, potassium orthophosphate,
Potassium pyrophosphate, potassium hexametaphosphate, amorphous P2Q-Na20 composition, amorphous P205 day Na20
-K20 composition, IJ acid type glass, etc. The above alkali metal borates used as modifiers include sodium borate (Na20/Yaku203), potassium borate (K20/Fat 203), lithium borate (
Li20, old 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. Sodium silicate dissolved in a modified sodium silicate aqueous solution has extremely high film-forming properties, especially when the value of x is 0.5 to 3. A few are notable. 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 strong the coating is applied, no matter how strongly it is applied, efflorescence is likely to occur, no matter how much dealkalization is applied.
Moreover, it lacks chemical resistance and 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. Such a modified sodium silicate aqueous solution is prepared, for example, as follows. That is, it is prepared by dissolving the above-mentioned sodium silicate in water to obtain an aqueous solution, and dissolving the above-mentioned modifier in this aqueous solution. In this case, the amount of the modifier to be used can be selected such that the modifier is converted into P2Q, 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 the solution so that the resulting modified sodium silicate aqueous solution becomes a transparent and uniform solution, or make the modifier an aqueous solution in advance and add it to the aqueous solution of sodium silicate. Mixing is performed. That is,
This is because when the modified sodium silicate aqueous solution becomes opaque, the transparency of the produced siliceous film tends to be impaired. Furthermore, when preparing the modified sodium silicate aqueous solution in this way, it is preferable to set the concentration of the modified sodium silicate aqueous solution to 1 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 coating work difficult, and the coating film tends to crack or foam when baked. This is because if the concentration is less than 1%, the effect will not be sufficiently exhibited. The modified lithium silicate aqueous solution to be applied on the siliceous film (first) formed by applying and competing the modified sodium silicate aqueous solution has the following general formula Lj20
・XSi02・yH20 (However, x is a positive number of 0.5 or more, y is 0 or a positive number)
Lithium 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. used.

Specific examples of this modifier are the same as those for the modified sodium silicate aqueous solution. Lithium silicate dissolved in a modified lithium silicate aqueous solution lacks film-forming properties compared to sodium silicate, but the value of x is 0.5 to 3.5.
A film having a thickness of 1 to 2 degrees can be sufficiently formed. However, when the value of x becomes 7.5 or more, the film-forming properties are greatly impaired. As described above, although lithium silicate has somewhat less film-forming properties than sodium silicate, the film formed by it has extremely high chemical resistance. In other words, the film formed by baking at a temperature of 20,000 or more for 0.5 minutes or more has acid resistance (10% HCI at room temperature 6
0 minutes) and alkali resistance (6 minutes at room temperature in 10% NaOH)
0 minutes). Furthermore, the film formed with lithium silicate has extremely low occurrence of efforescence, and the film formed after baking for more than 20,000 times can be exposed to carbon dioxide and sulfur dioxide gas atmospheres even without dealkalization treatment. It is something that does not change. As described above, the film formed from lithium silicate has high chemical resistance and efflorescence resistance, but is somewhat lacking in impact resistance and the like. The above-mentioned modifier is
This imparts impact resistance to the film, and further improves chemical resistance and efflorescence resistance. The preparation of the modified lithium silicate aqueous solution, the preferred amount of the modifier used, the preferred concentration of the modified lithium silicate aqueous solution, etc. are the same as in the case of the modified sodium silicate aqueous solution. The present invention relates to a modified sodium silicate aqueous solution that can form a siliceous film that has extremely high impact resistance and thermal shock resistance as well as efforescence resistance as described above, and a modified sodium silicate aqueous solution that has chemical resistance and resistance as described above. By using it together with a modified lithium silicate aqueous solution that can produce a siliceous film with extremely high efflorescence properties, the advantages of both are taken advantage of, resulting in improved impact resistance, thermal shock resistance, chemical resistance, and effluorescence resistance as a whole. A siliceous film with extremely high resence properties is formed 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 the acid aqueous solution, HN03, H3P04
, S04, HC1, H3803, H2C03, and aqueous solutions of organic acids. From the point of view of effectiveness, H
Preferably, an aqueous solution of N03 is used. In addition, aqueous solutions of salts that are acidic when dissolved in water include aluminum nitrate, nitrates such as magnesium nitrate, calcium nitrate, zinc nitrate, barium nitrate, sulfates such as aluminum sulfate, magnesium sulfate, calcium sulfate, zinc sulfate, etc. Phosphates such as aluminum phosphate, monobasic calcium phosphate, monobasic magnesium phosphate, monobasic iron phosphate, monobasic steel phosphate, monobasic zinc phosphate, etc., and calcium chloride, aluminum chloride, magnesium chloride, ammonium chloride, chloride Examples include aqueous solutions of hydrochlorides such as zinc.From the viewpoint of effectiveness, it is preferable to use an aqueous solution of nitrates, and it is particularly preferable to use an aqueous solution of aluminum nitrate. This is carried out by spraying the siliceous film with an aqueous solution, an aqueous solution of the above salt, or a mixed aqueous solution of both, or by immersing a product having a siliceous film in the above aqueous solution. Although it varies depending on the type of treatment agent, it is preferable to set the concentration to 1 to 20%.The treatment time also varies depending on the type of treatment agent and the concentration of the aqueous solution, but it is preferable to set the concentration to 0.5 to 3 powder 1. It is preferable to set it between.

In particular, rather than dealkalization using an aqueous acid solution,
It is preferable to perform the dealkalization treatment using an aqueous solution of a salt that becomes acidic when dissolved in water. This is due to the following reason. In other words, whether using an aqueous acid solution or a salt aqueous solution, alkali metals are eluted from the siliceous film by dealkalization, and traces of the elution are formed.However, dealkalization using an aqueous salt solution Then, 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 sodium silicate is applied to the substrate. The method of application is not limited. For example, spraying, brushing,
The substrate is soaked in an aqueous solution of sodium silicate. Next, the base material coated with the aqueous solution of sodium silicate is air-dried, and then pre-dried at a temperature of less than 100°C.

This pre-drying is performed to remove free water in the sodium silicate coating and to prevent foaming during subsequent baking at high temperatures. This pre-drying is usually
0. within a temperature range of 5000 or more and less than 100 ○.
It is carried out for 5 to 30 minutes. Next, the sodium silicate coating is baked at a high temperature to form a first siliceous coating. In this case, the baking is divided into two stages and is performed at a relatively low temperature (100 -
200℃), followed by high temperature (20,000℃)
If the secondary baking is carried out at a temperature of more than 400 oo, but not more than 400 oo, 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 causes were incomplete removal of free water in the silicate during drying and heat treatment. We discovered that heat treatment was performed under inappropriate conditions without fully understanding the dehydration reaction of silicate during heat treatment.We then conducted differential thermal analysis (DTA) to investigate the dehydration reaction of silicate during heat treatment. ) and calorimetric analysis (TGA).
At temperatures between 0 and 20,000, a reaction (possibly a dehydration reaction) that causes the formation of pinholes in the siliceous film occurs violently, so the silicate is heat-treated (primary baking) in this temperature range. After a sufficient dehydration reaction, it was discovered that the formation of small pores in the siliceous film was significantly reduced if heat treatment (secondary baking) at a temperature exceeding 200 oo and below 40,000 ℃ was carried out, and the baking treatment was carried out for 2 days. I decided to divide it into stages. This primary baking is 0.5~
From the viewpoint of effectiveness, it is preferable to carry out the treatment for about 30 minutes. The secondary baking done after the first baking is over 200qo and 400qo
It is preferable to carry out the reaction at the following temperature.

This secondary doming 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 a dealkalization treatment, if necessary, with an aqueous solution of the above-mentioned acid or an aqueous solution of a salt that exhibits acidity when dissolved in water.

The first siliceous film is imparted with phrefluorescence resistance by the modifier, and when it is subjected to dealkalization treatment in this manner, the efflorescence resistance is greatly improved. Next, a modified lithium silicate aqueous solution is applied onto the first siliceous film, and a series of treatments from application of the modified sodium silicate aqueous solution to a glazing treatment and the same process are performed to form a second siliceous film. 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 made of modified lithium silicate and has high efforescence resistance, but when it is dealkalized in this way, the efforescence resistance is further improved. This means that even if the resulting product is used under harsh conditions, no efflorescence will occur. Since the performance of the first and second silica coatings has been greatly improved by the modifier, they are not affected at all by such dealkalization treatment. The thickness of the first and second siliceous films is 0.1, respectively.
From the point of view of effectiveness, it is preferable to set the number to ~2 Buddhas.

In this way, it is highly transparent and has 4 holes (pinholes).
No formation, efflorescence resistance, chemical resistance,
A product having a siliceous film with extremely high impact resistance can be obtained.

That is, the siliceous coating of this product is pre-dried (to remove free water in the silicate that causes pore formation) at a temperature of less than 100 OO prior to high temperature competition treatment. Therefore, the formation of small pore distribution is prevented. The siliceous film is composed of two layers, and the surface side is made of a second siliceous film (formed from modified lithium silicate) that has extremely high chemical resistance and efflorescence resistance due to the modification agent. , since the base material side consists of the first siliceous film (formed from modified sodium silicate) which has extremely high impact resistance and thermal shock resistance due to the modifier, the advantages of the first and second siliceous films are As a result, the siliceous coating as a whole has extremely high chemical resistance, efflorescence resistance, impact resistance, and thermal shock 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 efflorescence can be further prevented, so the resulting product can be used under harsh conditions. However, no efflorescence occurs at all. 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 of high-purity aluminum plate specified by JIS (Sumitomo Light Metal Co., Ltd., AI070P, mountain purity 97% or more, 100 x 100 x 1 willow), which is buffed and then dealkalized with a neutral detergent. Chemical polishing (phosphoric acid 80% by volume, acetic acid 5% by volume, nitric acid 15% by volume, liquid temperature 10%)
It was diluted with inkstone sand for 3 times at 0°C), washed with water, washed with 10% by volume NO, and washed with water to give a mirror finish. Using this base material, as shown in Table 1 below, apply the silicate aqueous solution shown in the same table on the surface of the base material in the amount shown in the same table, heat treat it as shown in the same table, and then apply as necessary. Accordingly, a product having a siliceous film was obtained by dealkalization treatment.

Satoshi Tateji S Befune Tateji S Next, the performance of the siliceous film of the product having the siliceous film 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 film 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. The performance evaluation method shown in Table 2 was performed as follows.

{1} Appearance: The presence or absence of cracks was checked using a microscope (×100).

Color was visually observed. {2} Chemical resistance: 10%HC
Furnace paper (10%
3 layers of 10 ribs) were soaked in layers, placed on the surface of the test item, covered with a watch glass, left for 30 minutes at room temperature, washed with water, and observed with a magnifying glass (25x) for discoloration and corrosion. did.

(3) S02 gas test: Fill the bottom of the desiccator with water to a depth of 1.5 cm, put the test product there, then fill the desiccator with 400 kg of S02 gas to make it completely airtight, and leave it at room temperature in that state. Leave the report for 4 hours (at this time,
The inside of the desiccator was filled with a mixed gas of saturated water vapor at room temperature and 400% S02 gas.Then, the test specimen was taken out and placed in an open chamber of 100 to 13,000 to dry. The presence or absence of whitening (efflorescence) was examined using a magnifying glass (x25).
[4} Weather odor test and salt water fog test: JI
The weather meter test was conducted for 30 field hours and the salt water mist test was conducted for 10 cycles using a method based on S. ■ Heat resistance: 2
I went for 1 special time for 50oo. {6} Thermal shock resistance: After keeping the test product at 250 oo for 3 hours, it was immediately immersed in 2000 oo water and kept for 1 hour. This was regarded as one cycle, and 5 cycles were repeated. (7- Film thickness measurement: Measured with Permascope EWD8 (manufactured by Fischer (West Germany)).

Claims (1)

[Claims] 1 Sodium silicate represented by the following general formula (I) (I) Na_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 added in the produced siliceous film in terms of P_2O_5, B_2O_3, and Al_2O_3, respectively. Prepare a modified sodium silicate aqueous solution dissolved in a total proportion of 1 to 30 moles per 100 moles of SiO_2 component, and prepare a modified sodium silicate aqueous solution having the following general formula (II) (II) Li_2O x SiO_2
・Lithium silicate represented by yH_2O (where x and y are the same as in general formula (I)) is dissolved, and phosphates, borates and alkali metals belonging to Group 1a of the periodic table are used as modifiers. At least one of the aluminates is P_2O_5, P_2O_3, Al_2O_
A step of preparing a modified lithium 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 3, and the above sodium silicate aqueous solution. A step of applying the above to the surface of the base material, pre-drying at a temperature of less than 100°C, and then performing a baking treatment at a high temperature to form a first siliceous film; A process for producing a product having a siliceous film, comprising the steps of applying a modified lithium silicate aqueous solution, pre-drying at a temperature of less than 100°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 Sodium silicate represented by the following general formula (I) (I) Na_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 sodium silicate aqueous solution in which the following general formula (II) (II) Li_2O x SiO_
An aqueous solution of lithium 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
S in the produced siliceous film in terms of l_2O_3
A step of preparing a modified lithium silicate aqueous solution dissolved at a total ratio of 1 to 30 moles per 100 moles of iO_2 component, and applying the above modified sodium silicate aqueous solution to the surface of the substrate 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 lithium silicate aqueous solution is applied on the first siliceous film. After pre-drying at a temperature below °C, a baking treatment is further performed at a high temperature to form a second siliceous film, and after the formation of the first siliceous film and after the formation of the second siliceous film. After the formation of at least one of the siliceous films, 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. A method for manufacturing products with a film. 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.