JPS592308B2 - Film-forming composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a film-forming composition used for forming a non-flammable coating film.

BACKGROUND ART Conventionally, organic paints made of water-dispersible vinyl polymers containing almost no organic solvent have been used for various purposes as simple painting materials for indoors and outdoors. However, since these are mainly organic substances, they are easily combustible in the event of a fire, and cannot meet the demand for non-combustible paint films due to the recent increase in the number of high-rise buildings. In order to improve these defects in organic paints, water-soluble alkali silicates, which are inorganic binders, are used as paint binders. However, the coating film obtained by drying a paint using a water-soluble alkali silicate at room temperature has essentially poor water resistance. That is, there is a drawback that the coating film softens in water. In order to overcome such drawbacks of water-soluble alkali silicates, the present inventors have provided an inorganic coating composition containing an aqueous colloidal silica dispersion and an aluminum compound as main components (for example, Japanese Patent Application No. 106522/1983). etc)
In addition, we conducted intensive research to improve hardenability, water resistance, etc. Colloidal silica causes an aggregation reaction and gels when its surface charge balance is disrupted. There are many compounds that cause this gelation, including electrolyte compounds. As a result of examining these various colloidal silica flocculants, it has been found that the compounds that give the best results in terms of the hardness of the produced flocculates and their water resistance are metallic zinc and/or zinc compounds. However, when metallic zinc is simply added to an aqueous colloidal silica dispersion, a coagulation reaction occurs within a few minutes regardless of the amount added, resulting in a hard gel-like substance, which in this state is completely unusable as a paint. be. Therefore, as a result of intensive research on compounds that adjust the rate of agglomeration reaction between colloidal silica, metallic zinc, and/or zinc compounds, we found that the rate of aggregation reaction can be adjusted by simultaneously adding water-soluble organic amines. I understand. Furthermore, it has been found that the time required for aggregation can be freely adjusted by appropriately combining the amount of amine and the amount of metallic zinc and/or zinc compound used. The reason why amines can adjust the aggregation reaction rate between colloidal silica and zinc ions is that when amines are added to colloidal silica aqueous dispersions, amines selectively adsorb to the silanol groups on the surface of colloidal silica particles and react with zinc ions. This is thought to protect the active sites.

Therefore, the replacement of amines adsorbed on the silanol groups, which are the active sites of colloidal silica, with zinc ions in the solution becomes the rate-limiting step for the aggregation reaction, and the time required for the aggregation reaction becomes longer. That is, the reaction rate between colloidal silica and zinc ions can be adjusted by the combined use of a water-soluble organic amine. Based on the above research results, we have completed the invention of a film-forming composition with excellent curability and water resistance.

That is, the present invention provides colloidal silica aqueous dispersion (4)
, a water-soluble organic amine (B), a powdered silicic acid compound and/or a powdered aluminum compound (C), and a metal zinc and/or a zinc compound I)), and the above ( B) The molar ratio (amine/SiO2) of component and prisoner component is 0.01/1 to 1.0/1.
0, and the molar ratio of the D) component and the prisoner component (Zn/S
iO2: In the case of a zinc compound, converted to the number of moles of Zn) is 0.
01/1 to 1.0/1.0, and furthermore, the amount of silicon dioxide contained in the component (A) is less than S in the composition.
The present invention relates to a film-forming composition characterized in that the ratio of lO2/(SiO2+H2O) is 0.10 or more.

The inorganic coating of the present invention has excellent curability compared to the conventional coating compositions described above, and has significantly improved water resistance and adhesion of the cured coating. Since most of the constituent components of the composition are inorganic compounds, it is completely non-flammable even when burned with a gas flame.

The aqueous colloidal silica dispersion used in the composition of the present invention is S
An aqueous dispersion containing about 10 to 50% by weight of iO2,
It is stabilized by trace amounts of either alkali metal ions or ammonium ions. Further, an aqueous colloidal silica dispersion in which colloidal silica particles are modified with alumina or silicone can also be used.

Furthermore, the silica particles in the aqueous colloidal silica dispersion are extremely small and preferably have a particle diameter in the range of 1 to 100 mμ. Next, the amount of organic amines to be used is 0.01/1.0 to 1.0/1.0 in molar ratio (amines/SlO2) to SiO2 contained in the colloidal silica aqueous dispersion.
Use within the range.

If the amount of amine exceeds the above range, the film-forming composition exhibits irritating properties and may irritate the user's skin, eyes, nose, etc., which is not preferable in terms of handling. Furthermore, efflorescence may occur on the surface of the coating film, which may deteriorate the appearance of the coating film formed. In addition, if the amount of amine is less than the above range, when metal zinc and/or a zinc compound that easily ionizes in water and easily separates zinc ions is used as a curing agent, the reaction that causes rapid coagulation of colloidal silica will be suppressed. become unable. In other words, the pot life of the paint becomes extremely short, making it impossible to use it as a paint. As the water-soluble organic amine, for example, monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, aminoethylethanolamine, ethylenediamine, morpholine, and other water-soluble organic amines containing an amino group in the molecule can be used. Metallic zinc and/or zinc compounds are used to improve the curability and water resistance of the coating film, and the amount of zinc and/or zinc compounds used is determined by the molar ratio ( Zn/SiO
2: 0.01 (converted to the number of moles of Zn in the case of zinc compounds)
/1.0~1. It is in the range of O/1.0.

If the amount of metallic zinc and/or zinc compound exceeds the above range, when metallic zinc is used, metallic zinc will precipitate on the coating surface, resulting in poor coating surface condition. In the case of zinc compounds, phenomena such as yoking tend to occur on the coated surface, resulting in poor coated surface condition. Moreover, if it is used below the above range, the water resistance of the coating film will not be sufficient. Examples of the zinc compound used include zinc oxide, zinc hydroxide, zinc carbonate, zinc chloride, zinc alkali metal salt, zinc alkaline earth metal salt, zinc phosphate, and zinc ammonium salt. Examples of the powdered silicic acid compound and/or powdered aluminum compound in the present invention include α-type, β-type, cristobalite-type and tridymite-type quartz powder, fused silica powder, alkali silicate glass powder, aluminum oxide, aluminum hydroxide, silicic acid Aluminum, calcium aluminum silicate, and other inorganic pigments whose surfaces are treated with an aluminum compound, such as titanium oxide coated with aluminum hydroxide, are used.

These compounds may be used alone or as a mixture of two or more. Further, the powdered silicic acid compound and/or the powdered aluminum compound are used in such a proportion that the proportion of nonvolatile components in the paint is in the range of 40 to 90% by weight. If the amount of the silicic acid compound and/or aluminum compound exceeds the above range, the viscosity of the paint will increase significantly and the coating workability will deteriorate. On the other hand, if it is smaller than the above range, the physical shrinkage of the coating film during drying will be too large, making the coating film more likely to crack and resulting in poor film-forming properties. The particle size of the powdered silicic acid compound and powdered aluminum compound used is preferably in the range of 1 to 100 microns, particularly 8 to 50 microns.

The composition of the present invention also contains various coloring pigments such as titanium dioxide to give color to the coating film, and conventional paints such as clay, mica, talc, and carbonates of alkaline earth metals to improve the coating properties of the composition. Inert extender pigments, etc. used in

In addition, fluidity regulators such as bentonite and vegum,
Paint additives such as antifoaming agents and surfactants can also be used. Further, the amount of colloidal silica (SiO2) contained in the composition of the present invention is the same as that of water contained in the composition.
The sum of SlO2/SiO2+H2O must be 0.1 or more.

Paint films formed with values below the above will cause yoking,
Furthermore, the curability of the coating film is not sufficient. The film-forming composition of the present invention can be produced by a conventional coating method.

Preferably, first, a water-soluble organic amine is dissolved in an aqueous colloidal silica dispersion, and then a powder composition is added thereto and dispersed using mechanical force such as a vebble mill or Despa to form a paint, or a colloidal silica aqueous dispersion is dispersed to form a coating. A liquid containing a powdered silicic acid compound and/or a powdered aluminum compound, etc., dispersed in advance, and a water-soluble organic amine, a pigment, a surfactant, etc. dispersed in water are mixed before painting. Good method to use. The film-forming composition of the present invention can be applied to ceramic materials, glass substrates, concrete substrates,
Shows very good adhesion on mortar substrates, calcium silicate plates, slate plates, steel substrates, zinc-rich paint coatings, etc.

Furthermore, in the case of materials in which the paint suction phenomenon occurs in the above-mentioned base materials, this can be prevented by preheating to at least 40° C. or higher before painting. In addition, the coating methods for this composition include spray coating, roller coating, brush coating,
General methods such as curtain flow coater painting are used.

Note that drying is usually carried out at room temperature, but if it is desired to shorten the process, it is also possible to heat dry. Next, examples will be given to explain the present invention in more detail.

Note that the examples are not intended to limit the present invention. Examples 1 to 5 and Comparative Examples 1 to 3 Paints were made with the compositions shown in Table 1, and were sprayed onto a slate substrate with a spray gun to a dry film thickness of 70 μm to prepare test plates. .

Comparative Example 4 A 40% sodium silicate (NO2O.3Si02) aqueous solution was used instead of the colloidal silica aqueous dispersion of Example 1,
The other components were as per the formulation table, and the mixture was applied to a slate board in the same manner as in Example 1, and dried under the same conditions to prepare a test board.

The test results for Examples 1-5 and Comparative Examples 1, 2 and 4 are shown in Table 2.

Claims (1)

[Claims] 1 Consists of colloidal silica aqueous dispersion (A), water-soluble organic amines (B), powdered silicic acid compound and/or powdered aluminum compound (C), and metallic zinc and/or zinc compound (D) A film-forming composition and a molar ratio of the component (B) and the component (A) (amine/
SiO_2) is 0.01/1 to 1.0/1.0,
and the molar ratio of component (D) and component (A) (Zn/SiO
_2: In the case of zinc compounds, the number of moles of Zn) is 0.0
1/1 to 1.0/1.0, and furthermore, the amount of silicon dioxide contained in the component (A) is less than the amount of silicon dioxide in the composition.
A film-forming composition comprising a ratio of O_2/(SiO_2+H_2O) of 0.10 or more.