JPS6156259B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to film-forming compositions. More specifically, the present invention relates to a coating composition used for forming a nonflammable coating film and a topcoat coating on an inorganic zinc-rich paint coating. BACKGROUND OF THE INVENTION Conventionally, organic paints such as 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 nonflammable coatings due to the recent increase in the height of buildings. In addition, when such an organic paint is overcoated on an inorganic zinc-rich paint film, the interlayer adhesion between the organic paint film and the zinc-rich paint film is poor because the surface pH of the zinc-rich paint film is extremely high. It's bad. Furthermore, due to the inherent nature of organic paints, there are problems with organic solvent resistance, heat resistance, and chemical resistance (acid, alkali, etc.), and because they are relatively soft, they are not suitable for applications that require excellent wear resistance. use is restricted. In order to improve these defects of organic paints,
Water-soluble alkali silicates, which are inorganic binders, are used as paint binders, and they have properties unique to inorganic compounds, such as strong adhesive strength, bonding strength, excellent chemical resistance, nonflammability, and high hardness. Water-soluble alkali silicates contain a large amount of alkali metal ions, and the internal siloxane bonds are broken by the alkali metal ions, so paints containing water-soluble alkali silicates cannot be dried at room temperature. The resulting coating film has essentially poor water resistance. That is, there is a drawback that the coating film softens in water. In order to overcome these drawbacks of water-soluble alkali silicates, the present inventor has provided an inorganic coating composition containing a colloidal silica-aluminum compound as a main component (Japanese Patent Application No. 106522/1989, etc.). As a result of intensive research aimed at improving properties such as durability and water resistance, the present invention was completed. That is, the present invention provides a composition comprising a vehicle component containing an aqueous dispersion of unmodified or modified colloidal silica as a main component and a powder component containing a powdered aluminum compound as a main component, and a composition containing titanic acid, zirconic acid, and stannic acid. A film-forming composition comprising at least one of an alkaline earth metal salt of a selected metal oxide or a zinc salt of the metal oxide. The inorganic coating of the present invention has excellent curability and very good abrasion resistance compared to the conventional coating compositions described above, and the cured coating has excellent water resistance, solvent resistance, chemical resistance, The adhesion of the paint film has been significantly improved, and it is non-flammable even when burned with a gas flame. Furthermore, since all or most of the forming components of the film-forming composition of the present invention are inorganic compounds, all the essential drawbacks of the organic compounds described above can be improved, and the film-forming composition can be coated with an inorganic zinc-rich material. The interlayer adhesion with the film is also very good because it is a combination of inorganic and inorganic compounds. The unmodified colloidal silica aqueous dispersion, which is one of the unmodified or modified colloidal silica aqueous dispersions which is the main component of the vehicle component of the composition of the present invention, is SiO ₂
It is an aqueous dispersion containing about 10 to 50% by weight of sodium ions, 1% by weight or less in terms of Na ₂ O, and trace amounts of other alkali metal ions such as lithium ions and potassium ions. good. In addition, the silica particles in this aqueous colloidal silica dispersion are extremely small, with a particle size of 1 to 100 mμ.
range is desirable. Some representative examples of such aqueous alkali-stable colloidal silica dispersions are shown below.

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[Table] Examples of modified colloidal silica aqueous dispersions include those obtained by modifying the above-mentioned unmodified colloidal silica aqueous dispersions, such as lithium-modified and amine-modified ones. The lithium-modified colloidal silica aqueous dispersion is, for example, a mixture of a water-soluble lithium salt and a colloidal silica aqueous dispersion,
The mixing ratio is 1/3 or less in molar ratio (Li ₂ O/SiO ₂ ) when lithium is converted into lithium oxide (Li ₂ O) and all silica is converted into dry silica (SiO ₂ ). When the water-soluble lithium salt exceeds 1/3 in molar ratio (Li ₂ O/SiO ₂ ), the stability of colloidal silica deteriorates and gelation may occur during storage. Examples of the water-soluble lithium salt used include lithium hydroxide and lithium polysilicate. Amine-modified colloidal silica aqueous dispersion is a mixture of water-soluble organic amine and colloidal silica aqueous dispersion, and the mixing ratio is determined by the weight ratio of amines and silica contained in the vehicle (amines/SiO ₂ ) is less than 2/1. If the amount of amines exceeds the above range, the coating composition will be irritating and may irritate the user's skin, eyes, nose, etc., which is not preferable in terms of handling. Examples of water-soluble organic amines include mono-ethanolamine, di-ethanolamine, and tri-ethanolamine.
Examples include ethanolamine, isopropanolamine, ethylenediamine, isopropylamine, diisopropylamine, morpholin, and aminoethylethanolamine. In addition, in order to improve the flexibility of the coating film, a water-soluble or water-dispersible organic resin may be used in combination with an aqueous dispersion of unmodified or modified colloidal silica in the vehicle component. can. Water-soluble organic resins include (1) water-soluble alkyd resins whose carboxyl groups are neutralized with bases such as amines or ammonia, water-soluble acrylic resins,
Anionic water-soluble resins such as maleated oils and their derivatives, and those to which various anionic surfactants are added; (2) Polyethylenes made water-soluble by introducing polyethers such as polyethylene glycol or hydroxyl groups into the molecule. Nonionic water-soluble resins such as glycol-modified alkyd resins, polyvinyl alcohol, and methyl etherified polymethylolmelamine, as well as nonionic surfactants added to these resins, are available. Water-dispersible organic resins include (1)
Emulsions such as rubber latex, (2) vinyl acetate polymers, vinyl acetate-vinyl chloride copolymers, acrylic ester copolymers, and epoxy resins using nonionic or anionic surfactants or the water-soluble organic resins as emulsifiers, for example, WAV21 (Dainippon Ink Co., Ltd. product), Primal AC 22.55.33.C−72
(UCC product) etc. Alternatively, (3) there are emulsions in which an acid group such as a carboxyl group is introduced into the molecule, and the emulsion is neutralized with a base to become a self-emulsifying agent. Examples include acrylic resin emulsion, acetic acid emulsion, and high acid value alkyd resin emulsion. In addition, so-called epoxy resins containing two or more oxirane groups (epoxy groups) in the molecule can also be used as water-soluble or water-dispersible organic resins. It is also possible to use a polyamide resin in combination. That is, immediately before use, an aqueous dispersion consisting of a vehicle component containing an unmodified or modified colloidal silica aqueous dispersion, a water-soluble or water-dispersible organic resin, a powdered aluminum compound, a composite oxide and, if necessary, a pigment, etc. It is also possible to obtain a cured coating film by adding, mixing, and coating a curing agent. Such epoxy resins include Epolite, an epoxy resin made by reacting epichlorohydrin at both ends of polyethylene glycol.
Epoxy emulsions made by emulsifying 400E (Kyoei Oil Products) and Epon #828 (Ciel Chemical Products) with nonionic surfactants can be used. The amount of the water-dispersible or water-soluble organic resin is 1.0 parts by weight or less, preferably 0.6 parts by weight or less, as resin solids per 1 part by weight of silica solids in the vehicle component. If the mixed resin ratio exceeds 1.0, the hardness of the coating will decrease, making it difficult to form a practical coating. Further, when a lithium-modified or amine-modified colloidal silica aqueous dispersion is used as a vehicle component, a water-soluble transition metal salt may be included for the purpose of increasing water resistance and curability. Water-soluble transition metal salts include potassium dichromate, sodium dichromate, potassium chromate, sodium chromate, ammonium chromate, sodium molybdate, potassium molybdate, sodium tungstate, potassium tungstate, ammonium ferrous sulfate, Iron acetate, ferric ammonium oxalate, cobalt hydroxide, cobalt nitrite, potassium sodium, cobalt acetate, cobalt ammonium nitrate, cobalt ammonium phosphate, manganese oxide, sodium vanadate, potassium vanadate, and the like can be used. These may be used alone or as a mixture. In the present invention, one or two water-soluble salts of transition metals such as chromium, molybdenum, tungsten, iron, cobalt, manganese, vanadium, etc.
_The amount of the above-mentioned compound to be added is based on the molar ratio (ion of the above metal/SiO ₂ ) is less than 1/50. Within this range, various metal ions have the effect of improving the water resistance of the formed coating film and the curing properties of the coating film, but they are used at concentrations where this molar ratio is higher than 1/50 (large amount of metal ions). This acts as a crosslinking agent for the silanol groups (-SiOH) present on the surface of each colloidal silica particle and binds each colloidal particle, causing the colloidal particles to aggregate and gel. Examples of the powdered aluminum compound in the present invention include aluminum oxide, aluminum hydroxide,
Aluminum silicate, potassium aluminum silicate, calcium aluminum silicate, fired products of these aluminum compounds and metal oxides (e.g. titanium oxide, silicon dioxide), powders whose surfaces are treated with inorganic pigments with aluminum compounds, e.g. hydroxide Titanium oxide coated with aluminum can be used. These can be used alone or as a mixture of two or more. The mixing ratio of the vehicle component to the powdered aluminum compound is preferably 1/50 to 5/1, particularly preferably 1/10 to 4/1, in terms of weight ratio (SiO ₂ /powdered aluminum compound). In the present invention, a composite oxide is used to improve the curability and water resistance of the coating film. Alkaline earth metal salts of metal oxides selected from titanic acid, zirconic acid and stannic acid or zinc salts of the metal oxides (e.g. BaTiO ₃ , CaZrO ₃ , SrSnO ₃ ,
ZnTiO ₃ , ZnZrO ₃ , ZnSnO ₃ , etc.) are used. Hereinafter, the above salt will be simply referred to as a composite oxide. The amount of the composite oxide used is preferably in the range of 5/1 to 1/20 in terms of weight ratio (composite oxide/aluminum compound) to the aluminum compound used. If the mixing ratio is 5/1 or more, drying may be too rapid and cracks may occur on the coated surface. Furthermore, if the mixing ratio is less than 1/20, the effect of adding the composite oxide may not be sufficiently exhibited, and the curability and water resistance of the coating film may not be sufficiently improved. Furthermore, the composition of the present invention may contain glass powder in addition to the aluminum compound as a powder component in order to improve film-forming properties and thick coating properties. The glass powder used is preferably in the form of scales or fibers. Some typical powdered glasses include S glass flakes, E glass flakes (Nippon Glass Fiber Co., Ltd.),
Examples include chopped strand (Central Glass Fiber Co., Ltd.). Other common alkali silicate glass powders can also be used. In addition, the mixing ratio of glass powder to the aluminum compound used is 10/1 in weight ratio (glass powder/aluminum compound).
It is recommended to use: Mixing ratio is 10/1
If it exceeds , the curing properties of the coating film will deteriorate. In addition, powdered aluminum compounds, composite oxides,
The particle size of the glass powder is preferably in the range of 1 to 100 microns, particularly 3 to 50 microns. Furthermore, when the composition for forming an inorganic film of the present invention is used to protect a metal surface, especially a steel surface, zinc powder, lead powder, or other finely powdered metal pigment is used together with the powdered aluminum compound. For example, it is advantageous to use a mixture of lead oxide, lead chromate, zinc oxide, iron oxide, etc. to improve corrosion resistance. The composition of the present invention also contains titanium dioxide, carbon black, and various coloring pigments to impart color to the coating film, and clay, mica, talc, silicates, and alkaline earth metals to improve the coating properties of the composition. Inert extender pigments commonly used in paints, such as carbonates, etc., can be used. When applying a lysine finish using the composition of the present invention, examples of lysine materials include Gran Calcium (trade name, manufactured by Hoechst Gosei Co., Ltd.), Ishikawalite (trade name, manufactured by Ishikawa Light Industries Co., Ltd.), Ryton No. 2 (trade name, manufactured by Ishikawa Light Industries Co., Ltd.), etc. Name, manufactured by Ryton Kogyo Co., Ltd.), Hakuoh Crushed Stone 1
Rinhakuo Gorin (trade name, manufactured by Sankyo Seifun Co., Ltd.), Shuurcoat (trade name, manufactured by Asahi Kasei Industries, Ltd.), Perlite (manufactured by Mitsui Kinzoku Co., Ltd.), Unistone (trade name, manufactured by Onoda Unilon Co., Ltd.), Calcium carbonate #1 There are aggregates such as #5 (manufactured by Sankyo Seifun Co., Ltd.), and the appropriate particle size of these aggregates is 0.3 to 3 mm in diameter.
Particularly suitable is one with a diameter of 0.5 to 2 mm. The coating composition of the present invention also exhibits very good adhesion on glass substrates, slate substrates, concrete substrates, steel substrates, and zinc-rich paint coatings. Furthermore, paint additives such as fluidity regulators such as pentonite and antifoaming agents can also be used in the composition according to the present invention. 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 8 and Comparative Example 1 The vehicle components shown in Table 1 were blended in the proportions shown in Table 1 in the usual manner, diluted with water so that the nonvolatile content was 30% by weight, and then powdered aluminum and A composition for forming an inorganic film was prepared by blending the pigments. Spray this onto the slate board base material using a spray gun to a dry film thickness of 70μ. In addition, on steel plate substrates on which an inorganic zinc-rich paint film has already been formed, apply the same blended inorganic film-forming composition as above with a spray gun to a dry film thickness of 100%.
Spray to a thickness of μ. After drying the coated plates, various performance tests were conducted. The test results are shown in Table 2.
The table shows what was applied to the inorganic zinc-rich paint film. Comparative example 2 5 parts of polyvinyl alcohol (degree of polymerization 1000), water
50 parts of potassium persulfate, 0.3 parts of potassium persulfate, and 45 parts of vinyl acetate were mixed and stirred at 80°C for 5 hours while passing nitrogen through the mixture until the viscosity Z
A viscous emulsion of (Gardner, 20C) was obtained. This emulsion was applied to a slate base material in the same manner as in Examples 1 to 8, and dried under the same conditions to prepare a test plate. Comparative Example 3 A 40% sodium silicate (Na ₂ O・2.5SiO ₂ ) aqueous solution was made into a paint using the same powdered aluminum compound as in Example 1 (aluminum compound powder/SiO ₂ in a weight ratio of 200/100). It was applied to a slate base material in the same manner as in Example 1, and dried under the same conditions to prepare a test plate. The results of Comparative Examples 1, 2 and 3 are shown in Table 2. Comparative Example 4 An epoxy resin paint (vehicle: pigment = 1:2.2 epoxy resin polyamide curing agent) was applied to the base material in the same manner as in Example 1 (1) on top of the zinc-rich paint coating. It was coated on the surface and dried under the same conditions to prepare a test plate. The test results for Comparative Examples 1 and 4 are shown in Table 3. From the above test results, the composition of the present invention has extremely excellent curability, and the cured film thereof has high hardness as well as good water resistance, chemical resistance, adhesion, and impact resistance. is clear.

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Claims (1)

[Claims] 1. A composition consisting of a vehicle component containing an aqueous dispersion of unmodified or modified colloidal silica as a main component and a powder component containing a powdered aluminum compound as a main component, and a metal oxide selected from titanic acid, zirconic acid, and stannic acid. 1. A film-forming composition comprising at least one of alkaline earth metal salts of metal oxides and zinc salts of metal oxides.