JP5343197B2 - Water resistant material - Google Patents

Description

  The present invention relates to a structure of a water-resistant material, and more particularly to a water-resistant material having a structure in which a water-resistant film is coated on the surface of a powder or bulk material that reacts with water to form a hydrate.

  Reacts with so-called water such as oxide powder of magnesium, calcium, yttrium, composite oxide powder of perovskite, nitride of aluminum, silicon, boron, titanium, carbide, magnesium, aluminum, iron, copper, nickel, zinc, etc. The surface of the material that produces a hydrate is hydrolyzed in an atmosphere containing water to form a hydrate on the surface. If the material in which the hydrate is produced is left as it is in an atmosphere containing water, hydrolysis further proceeds and the original properties of the material are lost.

  For this reason, conventionally, a surface of a material that reacts with water to produce a hydrate is coated with a protective film for preventing hydration.

  The materials used for the protective coating include inorganic, organic, organic-inorganic composite, chelate, aqueous resin, silane coupling, etc., and are appropriately selected according to the characteristics of the material and the use of the surface-treated material. However, in all cases, it is essential to coat the entire material with a protective coating that is free of defects. However, in conventional methods, thin coatings are defective, so it is necessary to coat thick coatings. Yes.

  When the film is too thick, not only is an extra coating material required, but there is also a problem that the coating layer that is too thick hinders the original properties of the material.

  As a method of solving such a problem and forming a thin, defect-free protective film, a method using a chemical vapor deposition method or a hydrolysis reaction of a metal alkoxide (Patent Document 1), a monomer is first adsorbed on the material surface, A method of polymerizing this (Patent Document 2) and a method of adsorbing a chelate that forms a complex on the surface of the material (Patent Document 3) have been studied.

  However, in the method described in Patent Document 1, it is difficult to process a large amount of powder material at one time, and there is a disadvantage that it costs equipment and a solvent for dispersion, and the protective film is expensive. .

  On the other hand, it is necessary to coat each of the material particles by either the method of adsorbing the monomer described in Patent Document 2 and polymerizing the monomer, or the method of adsorbing the chelate described in Patent Document 3. Therefore, a large amount of solvent is required to monodisperse the material particles in the solvent, and after the treatment, a large amount of solvent needs to be removed. When the coating is formed, the material particles also agglomerate with each other, and the particle size distribution of the particles is greatly changed.

  Also, if the film is thin, the film will be destroyed due to the difference in thermal expansion between the film and material particles during the drying process, so it is necessary to coat the coating material thickly and in large quantities. The reality is that the objectives are not necessarily achieved.

  On the other hand, in the dry treatment that does not monodisperse in the solvent, there is a merit of not using the solvent, but since the monodispersed state cannot be achieved, the protective film is coated with the material particles agglomerated, and between each particle, Actually, there is a gap and sufficient water resistance cannot be obtained.

  Further, as a method of forming a protective film for preventing hydration on the surface of a metal material that reacts with water to produce a hydrate, a method for forming a silicate film on a metal surface of a material substrate and a fluoride film are provided. A method of forming is described in Patent Document 4. Furthermore, Non-Patent Document 1 describes that aluminum is immersed in a calcium hydroxide solution and then immersed in a silicate solution to form a composite film of silicate and calcium aluminate.

  However, although the protective film of the method described in Patent Document 4 and Non-Patent Document 1 can withstand an environment of a normal water or salt water spray, the film dissolves in a high-temperature alkaline aqueous solution. It cannot exhibit corrosion resistance at all.

JP 2008-74683 A Japanese Patent Laid-Open No. 08-000987 JP 2008-120636 A JP 2008-285737 A

Outline of the Annual Meeting of the Japan Institute of Light Metals Vol.93RD October 20, 1997 "Creation of aluminum chemical coating and two-step treatment with silicate" using calcium hydroxide as the base solution

  The present invention has been made in view of such problems, and its first problem is that it is excellent in protection effect even if it is thin, and has a water resistance coated with a protective film that does not break the film due to a difference in thermal expansion. Is to provide a sex material.

  A second problem is to provide a water-resistant material coated with a protective coating that does not dissolve or erode even when immersed in a hot alkaline aqueous solution.

  The inventor has conducted intensive research on the above problems, and found that the above problems can be solved by the following material structure.

  Means for achieving the first problem are as follows.

That is, when manufacturing a water-resistant material by coating a water-resistant film on the surface of a material selected from the group consisting of magnesia, aluminum nitride, and aluminum that forms a hydrate by reacting with water, the total mass of this material 0.01 to 0.87% by mass of water and at least one functional group selected from the group consisting of a sulfonic acid group, an amine, a quaternary amine salt, a phosphoric acid group, and a carboxylic acid group. By immersing and mixing the total amount of this material in an aqueous solution in which an unpolymerized organic compound having two hydroxyl groups is dissolved at a saturation adsorption concentration or more, 0.1 to 1% by mass of this material mass is converted into mass on the surface of this material. The hydrated layer is formed, and the growth of the hydrated layer is stopped by saturated adsorption of the unpolymerized organic compound on the surface of the hydrated layer. Functional group Has found that the adsorbed unpolymerized organic compound is cured by a chemical bond in which the hydroxyl groups are crosslinked by oxygen, forming a thin, water-resistant film that is excellent in protective effect and is not destroyed even by a difference in thermal expansion. . It was also found that even if no solvent is used, the powder material can be monodispersed and there is no aggregation between the powder materials.

The water-resistant material having the above water-resistant film has the following structure.
That is, magnesia generated by hydrate by reacting with water, a water-resistant material water resistant coating is coated on the selected surface of the material aluminum nitride, from the group of aluminum, the water resistance coating A hydrate layer having a thickness of 0.1 to 1% by mass of the material mass is formed on the surface of the material, and at least one hydroxyl group is formed on the surface of the formed hydrate layer. An unpolymerized organic compound having a single carboxylic acid group adsorbed at a saturated adsorption concentration, and the organic compound adsorbed at the saturated adsorption concentration is free from the hydrate layer. In this structure, the carboxylic acid group or hydroxyl group is cured by chemical bonding through oxygen crosslinking.

  If the thickness of the hydrate layer is less than 0.1% by mass in terms of mass, the film is too thin and defects are likely to occur, and sufficient water resistance cannot be obtained. In addition, when the amount is 1% by mass or less, there is no gap between adjacent hydrate layer crystals. However, when the amount exceeds 1% by mass, the hydrate layer grows too much, A gap is generated between crystals, and sufficient water resistance cannot be obtained. Therefore, the thickness of the hydrate layer is preferably in the range of 0.1 to 1% by mass in terms of mass.

  The actual water content for forming a hydrate layer in the range of 0.1 to 1% by mass is as shown below.

  In the following, the object is powder, but the water resistance is the same even in the case of a bulk body.

  In order to form a hydrate layer in a range of 0.1 to 1% by mass in terms of mass on the surface of magnesia powder, 0.030 to 0.300% by mass of water is necessary.

  In order to form a hydrate layer in the range of 0.1 to 1% by mass in terms of mass on the surface of the aluminum nitride powder, 0.068 to 0.680% by mass of water is required.

  In order to form a hydrate layer in the range of 0.1 to 1% by mass in terms of mass on the surface of the aluminum powder, 0.068 to 0.680% by mass of water is required.

  In order to form a hydrate layer in the range of 0.1 to 1% by mass in terms of mass on the yttria powder surface, 0.02 to 0.20% by mass of water is required.

窒化ボロン粉末表面に質量換算で、０．１〜１質量％の範囲の水和物層を形成するためには、０．０８７〜０．８７質量％の水分が必要である。

In order to form a hydrate layer in the range of 0.1 to 1% by mass in terms of mass on the boron nitride powder surface, 0.087 to 0.87% by mass of water is required.

  The unpolymerized organic compound is water-soluble, and the unpolymerized organic compound dissolved in water has a property of adsorbing to the hydrate layer. The concentration of the unpolymerized organic compound in water (mmol%) when the unpolymerized organic compound is adsorbed on the entire surface of the hydrate layer is the saturated adsorption concentration. Incidentally, in the case of magnesia and aluminum nitride, it is 20 mmol%.

When an aqueous solution in which an unpolymerized organic compound having a saturation adsorption concentration or more is dissolved and the powder come into contact, 5 μmol of organic matter is adsorbed on the hydrate layer per 1 m ^{2 of the} hydrate layer formed on the powder surface. That is, when 5 micromol of organic matter adheres per 1 m ^{2 of the} hydrate layer, the growth of the hydrate layer stops.

  As described above, the first role of the unpolymerized organic compound contained in the hydrate layer is that the thickness of the hydrate layer is 1% by mass or less, and there is no gap between crystals of adjacent hydrate layers. At this time, an unpolymerized organic compound is adsorbed (saturated adsorption) on the entire surface of the hydrate layer, and the growth of the hydrate layer is stopped to fix the hydrate layer.

  If the unpolymerized organic compound concentration is less than the saturated adsorption concentration, the hydration reaction does not stop, the hydrated layer grows, and finally a gap is generated between crystals of adjacent hydrated layers, resulting in water resistance. It becomes impossible.

Carboxylic acid group and a hydroxyl group of the unpolymerized organic compound liberated out of the hydrate layer, a carboxylic acid group together, or between a carboxylic acid group and a hydroxyl group, or by dehydration condensation with hydroxyl groups, or in the air It is cured by taking in oxygen and chemically bonding by cross-linking with oxygen to complete a water-insoluble and water-resistant protective film.

The second role of the unpolymerized organic compound in the present invention is to cause this curing action to complete a water-insoluble and water-resistant protective film. In addition, the adjacent carboxylic acid groups are chemically bonded to form a structure in which organic compound chains are stretched in a three-dimensional network, and this network structure is thin and free of defects and does not break due to a difference in thermal expansion. It is presumed that the hydrate layer can be formed.

  The third role of the unpolymerized organic compound in the present invention is to cause a three-dimensional network-like reinforcing structure in the hydrate layer.

  Formation of the hydrate layer of the present invention, adsorption of the unpolymerized organic compound, termination of the hydration reaction, chemical bonding by crosslinking with oxygen, and curing of the organic compound occur sequentially in sequence, thereby On the other hand, a protective film having insolubility and barrier properties is completed.

  Since it is essential that the organic substance in the present invention be adsorbed to the hydrate as a monomolecular layer, it is an essential condition to use an unpolymerized (monomer) organic compound. An organic compound having undergone polymerization is not preferable because the hydration reaction cannot be stopped.

  The unpolymerized organic compound is a so-called monomer, is water-soluble, and is glycolic acid, lactic acid, glyceric acid, malic acid, citric acid, ricinoleic acid, isocitric acid, creosote acid, glycine, 12 hydroxystearic acid, o- Hydroxycinnamic acid, p-hydroxycinnamic acid, m-hydroxycinnamic acid, 3-hydroxybutyric acid, 2-hydroxyhippuric acid, N- (2-hydroxyethyl) piperazine, 2- (hydroxymethyl) pyridine, 8- One or two or more selected from the group consisting of hydroxyquinoline-5-sulfonic acid, 4-hydroxyphthalic acid, and 2-hydroxyethylamine can be appropriately selected and used.

  In the present invention, although the solvent is not particularly used, the powder particles do not aggregate and monodisperse because the hydroxyl groups and carboxylic acid groups of the unpolymerized organic compound contained in the hydrate layer are directed outward. Thus, the surface is negatively charged. As a result, electrostatic repulsion between the powders is likely to occur, and it is assumed that the particles are less likely to aggregate.

  As a result of intensive studies on the means for achieving the second problem, the present inventors have obtained the following knowledge.

The first finding is that the structure of the water-resistant film formed on the material that forms a hydrate by reacting with water is an intermediate layer between the water-resistant film having the structure described in claim 1 and the surface of the material. The intermediate layer has a structure in which the metal component and calcium hydrate layer of the material, or a fluoride layer made of sodium fluoride and / or calcium fluoride, or the calcium hydrate and fluoride are formed. It was found that when a structure composed of the above composite layer was used, it was not eroded or dissolved in a high-temperature alkaline aqueous solution.

  And the thickness of this intermediate | middle layer discovered that the thickness of 0.1 mass% or more of this material mass was preferable in mass conversion. When the thickness of the intermediate layer is less than the lower limit value, the erosion resistance against a high-temperature alkaline aqueous solution does not appear. The upper limit is preferably about 1% by mass, and even if the upper limit is exceeded, the erosion resistance to a high-temperature alkaline aqueous solution does not change, so a thickness exceeding the upper limit is economically disadvantageous.

  In the present invention, the hot alkaline aqueous solution means an alkaline aqueous solution of 70 ° C. or higher. The composite layer of hydrate and fluoride means a layer in which the hydrate and fluoride are mixed or a layer in which a hydrate layer and a fluoride layer are laminated.

Second Knowledge In addition, in the water-resistant film having the structure described in claim 1, a structure in which a hydrate of a metal component and an alkaline earth metal component of a material is mixed, or a structure in which a fluoride is mixed, or this It has been found that when a structure in which both hydrate and fluoride are mixed is not eroded or dissolved in a high-temperature alkaline aqueous solution.

  And in any structure, when the material which a hydrate produces | generates by reacting with water is metal materials, such as Al and Si, it discovered that the effect was exhibited most.

  The inventors have found that the hydrate layer, the fluoride layer, or the total ratio of the hydrate and fluoride is preferably in the range of 0.1% by mass or more of the material mass in terms of mass.

  When the hydrate, fluoride, or the total ratio of hydrate and fluoride is less than the lower limit, erosion resistance to a high-temperature alkaline aqueous solution does not appear. The upper limit is preferably about 1% by mass, and even if the upper limit is exceeded, the erosion resistance to a high-temperature alkaline aqueous solution does not change, so a thickness exceeding the upper limit is economically disadvantageous.

Even if the surface of the material is simply coated with the metal component and calcium hydrate layer, or the fluoride layer, or the mixed layer of this hydrate and fluoride, the coating peels off immediately, Only when the structure obtained by the first and second findings is obtained, a film that is excellent in adhesion to the material and that does not erode or dissolve even in a high-temperature alkaline aqueous solution can be obtained.

  Based on the first and second findings, the following water-resistant coating can be formed.

First Method That is, an intermediate layer is formed between the water-resistant film having the structure according to claim 1 and the surface of the material, and the structure of the intermediate layer is changed to the metal component of the material and the hydrated layer of calcium. Or a fluoride layer made of sodium fluoride and / or calcium fluoride, or a structure made of a composite layer of this hydrate and fluoride, first, the treatment material (for example, Al) is treated with calcium water. It is formed by immersing in an aqueous solution of a hydrate, an aqueous solution of fluoride, or an aqueous solution in which hydrate and fluoride coexist, and then immersed in an aqueous solution that forms a water-resistant film having the structure according to claim 1. be able to.

In order to adjust the thickness of the intermediate layer, the concentration of each component in the aqueous solution of calcium hydrate, the aqueous solution of fluoride, or the aqueous solution in which the hydrate and fluoride coexist may be adjusted. Since the component ratio in the aqueous solution and the component ratio of the obtained film are substantially the same, the component composition in the film can be obtained by adjusting the composition of the aqueous solution.

Second Method In the water-resistant film having the structure according to claim 1, a hydrate of the metal component and calcium of the material, or a fluoride composed of sodium fluoride and / or calcium fluoride, or this In order to obtain a structure in which both a hydrate and a fluoride are mixed, the aqueous solution for forming the water-resistant coating according to claim 1 is added to a calcium salt, fluoride, or calcium salt and fluoride. It can be formed by immersing the treatment material in an aqueous solution in which both are present.

And in order to adjust the ratio of the hydrate or fluoride or both hydrate and fluoride to the range of 0.1 to 1% of the total mass of the material, What is necessary is just to adjust the density | concentration of the calcium salt and fluoride which exist in the aqueous solution for forming the water-resistant film of claim | item 1.

  Furthermore, it has been found that a film having the following structure can be obtained which has excellent adhesion and is not eroded or dissolved in a high-temperature alkaline aqueous solution. And the coating film of the following structure is more excellent in the erosion resistance with respect to the hot alkaline aqueous solution than the coating film of the structure obtained by said 1st, 2nd method.

  That is, a structure of a water-resistant film formed on a material that forms a hydrate by reacting with water is formed by laminating a silicate film on the surface of the water-resistant film having a structure according to any one of claims 2 to 5. When it is made a structure, or when it is made a structure in which a silicate is mixed in the water-resistant film having the structure described in any one of claims 2 to 5, it has excellent adhesion and a high-temperature alkaline aqueous solution. In addition, an extremely excellent film that is not dissolved or eroded can be obtained.

  And the thickness of the said laminated film of a silicate has the preferable range of 0.1 mass% or more of material mass in conversion of mass.

  When the thickness of the laminated silicate film is less than the lower limit, an improvement effect cannot be obtained as compared with the film having the structure obtained by the first and second methods. The upper limit is preferably about 1% by mass, and even if the upper limit is exceeded, the erosion resistance to a high-temperature alkaline aqueous solution does not change, so a thickness exceeding the upper limit is economically disadvantageous.

  Moreover, the ratio of the silicate of the film in which the silicate is mixed is preferably in the range of 0.1% by mass or more of the material mass in terms of mass.

  When the silicate ratio is less than the lower limit, an improvement effect cannot be obtained as compared with the coating film having the structure obtained by the first and second methods. The upper limit is preferably about 1% by mass, and even if the upper limit is exceeded, the erosion resistance to a high-temperature alkaline aqueous solution does not change, so a thickness exceeding the upper limit is economically disadvantageous.

  After immersing aluminum in an aqueous calcium hydroxide solution (alkaline earth metal salt aqueous solution) and then immersing in an aqueous silicate solution, hydrated layers of alkaline earth metal components (calcium aluminate) and silicate Even a conventional method for forming a composite coating (a so-called two-stage treatment described in Non-Patent Document 1) can provide a water-resistant coating with excellent adhesion, but this coating can be used in corrosive environments such as normal temperature water or normal temperature salt spray. Can withstand, but erodes and dissolves in a hot alkaline aqueous solution and does not exhibit water resistance.

  In contrast, in the present invention, the metal component of the material and the alkaline earth metal hydrate, or fluoride, or a combination of both the hydrate and fluoride, and a silicate (conventional two In addition, the coating component according to claim 1 is further combined with the coating component according to claim 1 and laminated so that the outermost layer is silicate, or the alkaline earth metal water is added to the coating according to claim 1. When hydrate is mixed with hydrate, fluoride, or both hydrate and fluoride, a water-resistant material with excellent corrosion resistance that does not erode or dissolve in hot alkaline aqueous solution is obtained. It has been found that this film has extremely superior properties that do not erode and dissolve in an alkaline aqueous solution at a higher temperature than the film having the structure obtained by the first and second methods.

  A method for forming a water-resistant film based on this finding is as follows.

  That is, the aqueous solution for forming the water-resistant film obtained by the first knowledge is added to an alkaline earth metal salt, fluoride, or an aqueous solution in which an alkaline earth metal salt and fluoride coexist. It can be formed by immersing a powder (for example, Al) to be subjected to water resistance treatment in a solution in which is mixed.

  Alternatively, after immersing the material to be subjected to water-resistant treatment in an aqueous solution for forming the water-resistant film, an alkaline earth metal salt, or a fluoride, or an aqueous solution in which both the alkaline earth metal salt and the fluoride are dissolved. Furthermore, it is obtained by performing a two-step dipping process in which the silicate-containing solution is dipped.

To adjust the thickness of the silicate multilayer coating, the silicic acid concentration of the silicate aqueous solution may be adjusted.
To adjust the thickness of the mixed silicate coating, the silicic acid in the aqueous solution in which the alkaline earth metal salt, fluoride and silicate are dissolved in the aqueous solution for forming the water-resistant coating according to claim 1 of the present invention. What is necessary is just to adjust the density | concentration of a salt. Since the component ratio in the aqueous solution and the component ratio of the obtained film are substantially the same, the component composition in the film can be obtained by adjusting the composition of the aqueous solution.

  In another aspect of the present invention, the powder component can be suitably applied to all inorganic and metal powders that generate hydrates by reacting with water, but hydrates are generated by reacting with water. The effect is most exerted on metal powders such as Al and Si powders.

  The metal component of the material and the hydrate layer of the alkaline earth metal component are, for example, calcium aluminate, magnesium aluminate, barium aluminate, strontium aluminate, etc. when the metal component is Al. In the case of Si, calcium silicate, magnesium silicate, barium silicate and the like.

  Silicate is a water-soluble silicate, for example, an alkali metal salt such as sodium silicate, potassium silicate, or lithium silicate.

  Further, when forming the water-resistant film of the present invention, various coloring dyes / pigments and wetting agents for improving coating properties, thixotropy imparting agents, diluting solvents, antifoaming agents, etc., as long as the effects of the present invention are not impaired. You may mix | blend suitably with the liquid mixture of water mentioned above and an organic compound.

  As a mixing method for uniformly dispersing the organic compound of the present invention with water and powder, a ball mill, a vibration mill or the like is suitable.

  The material applicable to the present invention is not particularly limited in shape, and can be appropriately used from a powdery material such as a plate shape, a scale shape, a spherical shape, and a crushed shape to a bulk material. Moreover, in the case of powder, there is no restriction | limiting in particular also about the particle size. Generally, it is applied to those having an average particle size of about 0.5 to 1000 μm.

  Materials applicable to the present invention include oxides such as magnesium, calcium and yttrium, composite oxides of perovskite, aluminum, silicon, boron, titanium nitride, carbide, magnesium, aluminum, silicon, iron, copper, nickel, zinc In general, inorganic and metallic materials that react with so-called water to form hydrates.

  The water-resistant material of the present invention has a property that it is not eroded or dissolved in a high-temperature alkaline aqueous solution. And the water-resistant film is thin, has an excellent protective effect, and has a characteristic that it is not broken by a difference in thermal expansion. In addition, when the material coated with the water-resistant film is a powder, the powder can be monodispersed without using a solvent, and there is no aggregation between the powders.

  Hereinafter, embodiments of the present invention will be described by taking magnesium oxide and aluminum nitride powder as examples. Note that this embodiment is specifically described for better understanding of the gist of the invention, and the present invention is not limited to this.

Example 1
An example of magnesia powder is shown.
A water resistance test was conducted by subjecting 100 g of magnesia powder having a specific surface area of 8 m ² / g to a water resistance treatment under the following conditions.

Conditions for water resistant treatment Lactic acid was used as the unpolymerized organic substance.
The saturated adsorption concentration of unpolymerized organic matter on magnesia powder is 6 micromol / m ² .
Hydrate thickness (in terms of mass) in the range of the present invention: Nos. 1 to 5: 5 levels The unpolymerized organic substances were set to 7 micromol / m ² (saturated adsorption concentration or higher) in all 5 levels. The values at each level are 0.1%, 0.23%, 0.32%, 0.65%, and 0.97% of the powder mass.

Comparative examples deviating from the range of the hydrate thickness of the present invention, Nos. 6 and 7: 2 levels The unpolymerized organic substances were set to 7 micromol / m ² (saturated adsorption concentration or more) in both 2 levels. The value of each level is 0.05% and 1.28% of the powder mass.

Comparative example with unpolymerized organic substance concentration less than the saturated concentration of the present invention, number 8, 9: 2 level (hydrate thickness is within the scope of the present invention)
Unpolymerized organic substance concentration: 3 micromol / m ² (hydrate thickness: 0.100% by mass)
Unpolymerized organic substance concentration: 4 micromol / m ² (hydrate thickness: 0.970% by mass)
No treatment: 1 level

  Table 1 shows the moisture percentage used in forming the hydrate layer and the results of the water resistance test.

Formation of Hydrate Layer Ball mill mixing 1 by adding water of the amount shown in Table 1, 100 g of magnesia, 7 μmol / m ² of lactic acid and zirconia balls in Nos. 1 to 5 to a ball mill container Went for hours. Thereafter, the temperature was kept at 80 ° C. to form a network (cross-linked with oxygen) between organic compounds to form a water-insoluble water-resistant protective film.

Similarly, in Nos. 6 and 7, water of the water amount shown in Table 1, 100 g of magnesia, 7 μmol / m ² of lactic acid, and zirconia balls were added to a ball mill container, and ball mill mixing was performed for 1 hour. . Thereafter, the temperature was kept at 80 ° C. to form a network (cross-linked with oxygen) between organic compounds to form a water-insoluble water-resistant protective film.

Similarly, in Nos. 8 and 9, in a ball mill container, water having the amount of water shown in Table 1, 100 g of magnesia, less than saturation concentration of 3 micromol / m ² , 4 micromol / m ² lactic acid, Zirconia balls were added, and ball mill mixing was performed for 1 hour. Thereafter, the temperature was kept at 80 ° C. to form a network (cross-linked with oxygen) between organic compounds to form a water-insoluble water-resistant protective film.
Each obtained powder was subjected to a water resistance test.

The water resistance test was performed as follows.
In a 100 ml plastic container with a lid, 10 g of powder and 50 ml of distilled water were placed, and set on a shaker and stirred so that the suspension did not precipitate. The suspension was collected at a predetermined time, and the amount of powder hydrate contained therein was measured.

  In the case of the untreated powder, as soon as the powder was put into distilled water and stirred, the pH became 11, and the hydration reaction proceeded. It was completely hydrated after 100 hours. The specific surface area was 5 times or more, and it was confirmed that fine magnesium hydroxide was formed.

Results In the range of the present invention, even after 100 hours, the increase in hydrate was 1.3 to 1.8, which was a very small increase. It has been confirmed that the present invention is extremely excellent as a water-resistant protective film. On the other hand, in the comparative example deviating from the scope of the present invention, a significant increase in hydrate was confirmed.

Confirmation Test for Existence of Crosslinked Structure by Oxygen As a result of measuring ultraviolet and infrared absorption spectra of the sample powder of No. 3, some hydroxyl groups of the unpolymerized organic compound of the present invention were found on the surface of the water-resistant powder It reacted, and it has confirmed that the crosslinked structure by oxygen was producing | generating.

Example 2
An example of aluminum nitride powder is shown.
A water resistance test was performed on 100 g of aluminum nitride powder having a specific surface area of 3.2 m ² / g under the following conditions.

Conditions for water-resistant treatment Malic acid was used as the unpolymerized organic substance.
The saturated adsorption concentration of the unpolymerized organic substance on the aluminum nitride powder is 5 micromol / m ² .

Hydrate thickness (in terms of mass) in the range of the present invention: Nos. 1 to 5: 5 levels The unpolymerized organic substances were set to 7 micromol / m ² (saturated adsorption concentration or higher) in all 5 levels.
The hydrate thickness (in terms of mass) is 0.1% by mass, 0.15% by mass, 0.30% by mass, 0.73% by mass, and 1.00% by mass of the powder mass.

Comparative example deviating from the range of the hydrate thickness of the present invention, No. 6, 7: 2 level The unpolymerized organic substance was set to 7 micromol / m ² (saturated adsorption concentration or more) in both 2 levels.
Hydrate thickness: 0.006%, 1.20% by weight of powder weight

Comparative example with unpolymerized organic substance concentration less than saturated adsorption concentration of the present invention, number 8, 9: 2 level (hydrate thickness is within the scope of the present invention)
Unpolymerized organic substance concentration: 3 micromol / m ² (hydrate thickness: 0.20% by mass)
Unpolymerized organic substance concentration: 4 micromol / m ² (hydrate thickness: 1.00% by mass)
No treatment: 1 level

  Table 2 shows the moisture% used in forming the hydrate layer and the results of the water resistance test.

Formation of Hydrate Layer In a ball mill container, add water of the amount shown in Table 2, 100 g of aluminum nitride powder, Nos. 1-5, 7 micromol / m ² malic acid, and zirconia balls, Ball mill mixing was performed for 1 hour. Thereafter, the temperature was kept at 80 ° C. to form a network (cross-linked with oxygen) between organic compounds to form a water-insoluble water-resistant protective film.

Similarly, in Nos. 6 and 7, ball mill mixing 1 was conducted by adding water of the amount shown in Table 2, 100 g of aluminum nitride powder, 7 micromol / m ² malic acid, and zirconia balls to a ball mill container. Went for hours. Thereafter, the temperature was kept at 80 ° C. to form a network (cross-linked with oxygen) between organic compounds to form a water-insoluble water-resistant protective film.

Similarly, in Nos. 8 and 9, in a ball mill container, water having the amount of water shown in Table 2, 100 g of aluminum nitride powder, and 3 μmol / m ² and 4 μmol / m ² apples less than the saturation concentration. Acid and zirconia balls were added and ball mill mixing was performed for 1 hour. Thereafter, the temperature was kept at 80 ° C. to form a network (cross-linked with oxygen) between organic compounds to form a water-insoluble water-resistant protective film.
Each obtained powder was subjected to a water resistance test.

The water resistance test was performed in the same manner as in Example 1.
Specifically, 10 g of powder and 50 ml of distilled water were placed in a 100 ml plastic container with a lid, and the mixture was set on a shaker and stirred so that the suspension did not precipitate. A suspension was taken at a predetermined time, and the amount of powder hydrate contained therein was measured.

  In the case of the untreated powder, as soon as the powder was put into distilled water and stirred, the pH became 9 or more, and the hydration reaction proceeded. It was completely hydrated after 100 hours. The specific surface area became 10 times or more, and it was confirmed that aluminum hydroxide was formed.

Results In the range of the present invention, even after 100 hours, the increase in hydrate was 1.8-2.3, which was a slight increase.
On the other hand, in the comparative example which deviates from the scope of the present invention, a significant increase (12 to 81) of hydrate was confirmed.
It has been confirmed that the present invention is extremely excellent as a water-resistant protective film.

  For the sample powder of No. 3, a confirmation test for the presence of a crosslinked structure due to oxygen on the surface of the water-resistant powder was performed in the same manner as in Example 1, and the presence of the crosslinked structure due to oxygen could be confirmed.

Example 3
An example in which a hydrate and a fluoride of an alkaline earth metal component are mixed in a water resistant film will be shown.

  Aluminum powder (100 g) with a center particle size of 150 μm, calcium hydroxide (0.1 g), glycine (0.5 g), 12-hydroistearic acid (0.15 g), citric acid (0.5 g), fluoride Sodium (0.5 g), water (1 g) and ethanol (5 g) were placed in a plastic ball mill pot and mixed for 3 hours. The taken out powder was washed and dried at 80 ° C.

  As a result, the structure of the surface of the obtained powder was determined by X-ray diffraction measurement. As a result, calcium aluminate hydrate and aluminum fluoride, calcium fluoride, calcium complex, aluminum complex were formed on the surface of the aluminum powder. It was a composite film in which

The thickness of the film was equivalent to approximately 1% of the powder in terms of mass.
This water-resistant powder (10 g) was placed in a sodium hydroxide solution (1 mol / L, 300 ml) at 70 ° C. and stirred for 5 hours.
After dehydration and filtration, the residue was subjected to X-ray diffraction measurement and thermal analysis.
The main component of the residue was aluminum metal. The weight loss after the treatment was only 5% with respect to the weight before the alkali solution treatment.

Comparative Example On the other hand, aluminum powder (100 g) having a center particle diameter of 150 μm, calcium hydroxide (0.1 g), sodium fluoride (0.5 g), water (1 g), and ethanol (5 g) were added to a plastic ball mill pot. The ball mill was mixed for 3 hours. The powder taken out was washed and dried at 80 ° C., and then the treated powder (10 g) was placed in a sodium hydroxide solution (1 mol / L, 300 ml) at 70 ° C. and stirred for 5 hours.
The treated powder was completely dissolved in a sodium hydroxide solution, and no residue was observed after dehydration and filtration.

  This confirmed that the water-resistant powder of the present invention was hardly eroded and dissolved in the hot alkaline aqueous solution.

Example 4
By adjusting the ratio of glycine and sodium fluoride in Example 3 above, three types of water-resistant powders of 0.05%, 0.1% and 0.5% in terms of mass were prepared, and each powder was carried out. Corrosion resistance to the high-temperature alkaline aqueous solution was evaluated in the same manner as in Example 1.

Results About 0.05% of the powder, no residue was observed after dissolution in the solution.
The 0.1% powder had a weight loss of 10%.
For 0.5%, the weight loss was 5%.
It has been confirmed that the water-resistant powder of the present invention has extremely excellent corrosion resistance with respect to a hot alkaline aqueous solution.

Example 5
An example in which a hydrate layer of an alkaline earth metal component is laminated under the water-resistant film having the structure described in claim 1 is shown.

  Aluminum powder (100 g) with a center particle size of 80 μm, calcium hydroxide (0.25 g), sodium fluoride (0.5 g), water (1 g), and ethanol (9 g) are placed in a plastic ball mill pot for 30 minutes. The ball mill was mixed. By X-ray diffraction method, it was confirmed that aluminum fluoride, calcium aluminate, calcium hydroxide, and aluminum hydroxide were present in the primary treated product. This primary treated product, 12 hydroxystearic acid (0.5 g) and N- (2-hydroxyethyl) piperazine (0.5 g) were placed in a plastic ball mill pot and mixed for 3 hours. This secondary treated product was washed and dried at 80 ° C.

  By this X-ray diffraction method, complexes and hydrates composed of aluminum fluoride and calcium aluminate, aluminum, calcium and organic components were confirmed in the secondary treated product. From this, it is inferred that a complex and a hydrate composed of aluminum, calcium, and organic components were formed on the aluminum powder surface on the aluminum fluoride and hydrate, and calcium aluminate.

  The thickness of the intermediate layer was equivalent to 1% in terms of mass.

  This water-resistant powder (10 g) was placed in a sodium hydroxide solution (1 mol / L, 300 ml) at 70 ° C. and stirred for 5 hours. After dehydration and filtration, X-ray diffraction measurement and thermal analysis were performed. The main component of the residue was aluminum metal. The weight loss after the treatment was only 3% with respect to the weight before the alkali solution treatment.

It is effective for water-resistant treatment of magnesia filler and aluminum nitride filler mixed in resin used for semiconductor encapsulation. It is effective for casting of aluminum nitride powder and granulation using a water binder, and can be expected to be widely used by manufacturers of aluminum nitride. It can also be used for water resistance treatment of Al and water resistance treatment of magnesia raw materials for refractories.

Claims (5)

A water-resistant material in which a water-resistant film is coated on the surface of a material selected from the group consisting of magnesia, aluminum nitride, and aluminum that forms a hydrate by reacting with water,
The water-resistant film is
Unpolymerized having at least one hydroxyl group and at least one carboxylic acid group on the surface of the hydrate layer having a thickness of 0.1 to 1% by mass of the material mass formed on the surface of the material. The organic compound is adsorbed at a saturated adsorption concentration,
In addition, the organic compound formed by adsorption at the saturated adsorption concentration is a water-resistant structure having a structure cured by chemically bonding a carboxylic acid group or a hydroxyl group of an unpolymerized organic compound liberated outside the hydrate layer by cross-linking with oxygen. Sex material. Wherein becomes an intermediate layer between the water-resistant coating and the material surface is formed, the intermediate layer is made of a metal component and a hydrate layer of calcium or sodium fluoride, or / and calcium fluoride of the material fluoride The water resistant material according to claim 1, comprising a compound layer or a composite layer of calcium hydrate and fluoride.   The water-resistant material according to claim 2, wherein the thickness of the intermediate layer is 0.1% by mass or more of the material mass in terms of mass. In the water-resistant film, the metal component of the material and calcium hydrate, or the fluoride composed of sodium fluoride and / or calcium fluoride, or both the calcium hydrate and fluoride are mixed. The water resistant material according to claim 1. The hydrate water-resistant coating or in the proportion of fluoride, or the total proportion of the fluoride and the hydrate, are of said material mass in mass conversion, according to claim 4 is at least 0.1 wt% Water resistant material.