JPS623114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has excellent storage stability and pot life.
The present invention relates to an inorganic coating composition with a long life and excellent water resistance and weather resistance. Conventional inorganic coating compositions are generally composed of an aqueous silicate solution as a binder and phosphoric acid or a phosphate salt as a hardening agent. However, in these conventional inorganic coating compositions, since the silicate aqueous solution and the curing agent have strong reactivity, when the two are mixed, the pot life is extremely short, making it impractical. Furthermore, if the amount of curing agent used is reduced in order to extend the pot life, the performance of the cured film will be significantly deteriorated, which is not preferable. Furthermore, in order to improve these defects, there is a method of first applying a silicate aqueous solution and then applying a hardening agent thereon and curing it, but this method complicates the painting process and is disadvantageous in practice. Furthermore, the cured films of these conventional inorganic coating compositions also have the defect of poor water resistance and weather resistance. The present inventors have removed the above-mentioned defects, and have achieved a high degree of water resistance, high surface hardness, excellent chemical resistance and weather resistance, and because it is an inorganic material, it is nonflammable and does not generate toxic gas. The present invention was arrived at as a result of intensive research to obtain an inorganic coating composition which, in addition, has excellent storage stability and is easy to work with. That is, the present invention provides a compound having the general formula M ₂ O.XSiO ₂ (where M is an alkali metal or N(CH ₂ OH) ₄ , N
(C ₂ H ₄ OH) ₄ , N(C ₂ H ₄ OH) ₃ , C(NH ₂ ) ₂ NH, where X is a positive number of 0.5 or more) and/or the water-soluble silicate A modified product obtained by modifying a silicate with a calcium or magnesium metal fluoride or a zirconium or vanadium metal oxide
To 100 parts by weight, 20 to 100 parts by weight of a reaction product of an alkali metal of Group A of the Periodic Table or a calcium metal hydroxide and/or a calcium metal oxide and a condensed phosphate and/or a phosphate. The present invention relates to an inorganic coating composition characterized by containing the following. The aqueous solution of water-soluble silicate M _{2 O.} There are aqueous solutions such as amine silicate consisting of silicic acid and guanidine silicate consisting of guanidine and silicic acid. Specifically, alkali metal silicates include sodium silicate, potassium silicate, lithium silicate, etc. Quaternary amine silicates include tetramethanolammonium silicate and tetraethanolammonium silicate, and tertiary ammonium silicates include silicic acid. Examples include triethanolammonium. Colloidal silica may be mixed with this aqueous solution of water-soluble silicate. The modified water-soluble silicate in the present invention is obtained by modifying the water-soluble silicate with a calcium or magnesium metal fluoride such as calcium fluoride or magnesium silicofluoride, or a zirconium or vanadium metal oxide. . These modified water-soluble silicates contain one or more mixtures of the above-mentioned water-soluble silicate aqueous solutions, and one or more mixtures (modifier) selected from the above-mentioned fluorides and oxides. can be obtained by reacting them in a conventional synthesis reaction vessel at room temperature or by heating and stirring. In the case of heating and stirring, about 50 to 100 at normal pressure
A reaction time of about 1 to 72 hours at <0>C is desirable. It is also possible to complete the reaction in a shorter time by using a pressure-resistant reactor such as an autoclave and raising the reaction temperature to 100°C or higher. The mixing ratio (weight ratio) of the water-soluble silicate and the above-mentioned modifier is 0.1 to 30 parts, preferably 0.5 to 20 parts, of the modifier per 100 parts by weight (hereinafter referred to as parts) of the solid content of the water-soluble silicate. The range is appropriate. In the present invention, an aqueous solution of a modified water-soluble silicate obtained as follows provides an inorganic composition having better performance in water resistance, weather resistance, etc. than an aqueous solution of an unmodified water-soluble silicate. . In other words, an inorganic coating composition using an aqueous solution of an unmodified water-soluble silicate as a binder can form a coating with sufficient durability, but when a modified water-soluble silicate is used as a binder, the coating composition is even more durable. A coating film is obtained. Further, the curing agent component used in the present invention is composed of a reaction product of a hydroxide and/or oxide of a calcium metal in Group A of the periodic table and a condensed phosphate and/or phosphate. The hydroxides of Group A and calcium metals of the periodic table used here include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, etc., and the oxides include calcium oxide. can give. In addition, examples of phosphates include aluminum, calcium, magnesium, zinc, silicon,
Orthophosphates, polyphosphates, metaphosphates, ultraphosphates, etc. of titanium, manganese, zirconium, etc. can be used. In addition, as the condensed phosphate, one or a mixture of two or more selected from primary phosphates and secondary phosphates such as aluminum, calcium, magnesium, manganese, zinc, etc. Examples include condensed phosphates obtained by neutralizing with hydroxides or salts of metals belonging to the group and/or metal composite oxides and then drying or baking. The hydroxides of metals belonging to groups of the periodic table used to obtain the above-mentioned neutralized condensed phosphates include:
Examples include calcium hydroxide, barium hydroxide, aluminum hydroxide, titanium hydroxide, etc. Salts include metal halides such as aluminum chloride, aluminum fluoride, calcium sulfate, magnesium carbonate, calcium carbonate, aluminum nitrate, and sulfuric acid. Examples include salts, carbonates, and nitrates. Composite oxides of metals include metal compounds such as oxides, hydroxides, and carbonates of metals in the periodic table group such as magnesium, calcium, and zinc, and oxides of silicon, titanium, zirconium, boron, and aluminum, and water. A mixture of oxide and carbonate is used which is calcined at about 500 to about 1200°C. (In the present invention, these phosphates and condensed phosphates are referred to as phosphorus-based compounds.) The curing agent components that can be used in the present invention include the above-mentioned phosphorus-based compounds, lithium, sodium, potassium, etc. The hydroxide of a metal belonging to the above group and/or the hydroxide and/or oxide of a calcium metal are reacted.
This reaction can be carried out simply by mixing the two in an aqueous medium at room temperature. In addition, this reaction can be performed using a ball mill,
The pulverization and mixing may be carried out using a mixing/dispersing device such as a colloid mill, sand mill, or attritor. If the reaction needs to be completed in a short time, heating may be used. In this reaction, the composition ratio of the phosphorus compound and the metal hydroxide varies depending on the purpose of use, but the pH of the aqueous solution of the product after reaction is in the range of 5 to 10.5, preferably in the range of 6 to 9.5. It is necessary to mix them so that If the pH is lower than 5 or higher than 10.5,
This is not preferable because the hydrolysis of the phosphorus compound becomes significant and the storage stability decreases. In addition, if the composition ratio of both of these is shown quantitatively, 100% of phosphorus compounds
It is necessary to mix the metal hydroxide in a range of 0.01 to 1.0 gram equivalent per part by weight. The concentration of these aqueous dispersions is 10% by weight or more, and in view of convenience in handling, it is particularly desirable that the concentration is 30 to 70% by weight. In the inorganic coating composition of the present invention, the blending ratio of the binder and the above-mentioned reaction product of the metal hydroxide and the phosphorus compound is 100 parts by weight of the former and 20 to 100 parts by weight of the latter. Use in proportions. The pigments, fillers, and additives may be color pigments, fillers, and additives commonly used in the paint industry. Conventionally, there is a method of using a reaction product of a water-soluble silicate and a condensed phosphate as a hardening agent for silicate-based inorganic coating compositions, but in this method, the aqueous dispersion of the hardening agent is Coarse particles with a particle size of 100μ or more are produced. This is thought to be because the silica ions contained in the water-soluble silicate further agglomerate due to phosphoric acid and metal ions dissolved from the phosphorus compound in the curing agent dispersion during storage. Therefore, the storage stability of the so-called curing agent dispersion was not sufficient. The curing agent component applied in the present invention can be obtained as described above, but by neutralizing the phosphorus compound with a metal hydroxide in the reaction system for obtaining the curing agent component, the phosphate Because the buffering effect of phosphorus compounds works and the hydrogen ion concentration is kept almost constant, hydrolysis of phosphorus compounds is prevented.
Furthermore, since there are no components that aggregate even when the pH is slightly lowered, the stability of the dispersion of the curing agent component obtained in the present invention is significantly improved, and therefore the inorganic composition obtained by mixing with the binder is The usage time becomes extremely long. The composition obtained according to the present invention is effective as a coating material, and conventional methods such as spray coating, brush coating, and roller coating can be used. Further, when the film is formed by hardening the film by heating, the film is hardened by baking at a temperature in the range of 150 to 300°C. The composition of the present invention can be applied to asbestos cement, concrete, mortar, calcium silicate board, gypsum board, other inorganic building materials, metal, glass, and the like. The composition of the present invention has excellent water resistance and weather resistance, the storage stability of the curing agent dispersion is excellent, and the inorganic composition has a long pot life, so it is easier to handle than conventional inorganic compositions. Therefore, it has a wide range of industrial applicability. Next, in order to further embody the content of the present invention,
This will be explained using manufacturing examples and examples. Note that in the following description, parts and % indicate parts by weight and % by weight. Production example of binder Production example 1 Tetraethanolammonium silicate 20% aqueous solution
10 parts, 20% aqueous solution of lithium silicate (molar ratio 4.8)
10 parts, sodium silicate (mole ratio 3.2) in the reaction kettle
100 parts of a 40% aqueous solution of , 0.5 parts of vanadium pentoxide, 1 part of calcium fluoride, and 1 part of zirconium oxide were mixed, and 80 parts of the binder obtained by reacting at 100°C for 10 hours with stirring were added to obtain the binder. Ta. Production example 2 40% of sodium silicate (molar ratio 2.5) in the reaction pot
70% aqueous solution and 40 parts of potassium silicate (molar ratio 3.5)
% aqueous solution, 2 parts of magnesium silifluoride, 1 part of zinc oxide, and 20 parts of water, and heated to 60°C while stirring.
A binder was obtained by reacting for 24 hours. Example 1 Zinc titanate 60 obtained by mixing 30 parts of zinc oxide and 20 parts of titanium oxide and baking at 1200°C for 1 hour.
110 parts of a 50% aqueous solution of monobasic aluminum phosphate
1 part, and 45 parts of monomagnesium phosphate powder, stir well, further add 20 parts of silica powder, stir, and then bake in a soaking dryer at 250°C for 3 hours to obtain condensed phosphorus. 26.5 parts of acid salt, 3.5 parts of aluminum orthophosphate, 1.8 parts of lithium hydroxide, 1.2 parts of calcium oxide, 20 parts of chromium oxide, 3 parts of clay, 0.2 parts of sodium octylsulfosuccinate, 80 parts of water
The parts were placed in a pebble mill and mixed for 24 hours.
The mixture was reacted and dispersed (30 μm or less as measured by a finesse gauge) to obtain a green aqueous dispersion of the curing agent component. After storing this product at 30℃ for 90 days, mix 100 parts of this product with 100 parts of binder and spray the obtained inorganic composition onto a slate board to form a thick film.
It was coated to a thickness of 40μ and heated at 260°C for 15 minutes to cure. The performance test results of the obtained coating film are shown in Table 1. Example 2 50 parts of calcium silicate and 50 parts of magnesium carbonate, which were obtained by mixing 60 parts of calcium oxide and 40 parts of silica powder and baking at 1200°C for 4 hours, were added to 150 parts of a 50% aqueous solution of monobasic aluminum phosphate. The mixture was added to a phosphate consisting of 20 parts of calcium pyrophosphate and 30 parts of dibasic zinc phosphate, and the mixture was thoroughly mixed and stirred.
Furthermore, 10 parts of fine silica powder and 100 parts of water were added and thoroughly kneaded. This stuff at 400℃ 5
The mixture was calcined for a period of time to obtain a condensed phosphate. Next, 35 parts of this condensed phosphate, 5 parts of zinc phosphate, 2 parts of aluminum silicate, 0.2 parts of sodium pyrophosphate, 8.5 parts of sodium hydroxide, 20 parts of titanium oxide, and 45 parts of water were charged into a pebble mill, which took 10 hours. The mixture was mixed, reacted, and dispersed (30μ or less as determined by a finesse gauge) to obtain a white colored aqueous dispersion of the curing agent component. After storing this material at 40℃ for 30 days, 100 parts of this material was mixed with 250 parts of a binder, and the obtained inorganic composition was spray-painted on a slate board.
It was cured by heating at ℃ for 30 minutes. The performance test results of the obtained coating film are shown in Table 1. Comparative Example 1 26.5 parts of the condensed phosphate obtained in Example 1, 3.5 parts of aluminum orthophosphate, 20 parts of chromium oxide,
3 parts of clay, 0.2 parts of sodium octylsulfosuccinate, and 80 parts of water were placed in a pebble mill and dispersed to a particle size of 30μ or less. After storing this product at 30℃ for 90 days, this product
Mix 100 parts of the inorganic composition with 100 parts of the binder and spray the resulting inorganic composition onto a slate board to a film thickness of 40 mm.
It was painted so that it had a thickness of μ, and was cured by heating at 260°C for 15 minutes. Comparative Example 2 26.5 parts of the condensed phosphate obtained in Example 1, 3.5 parts of aluminum orthophosphate, 10 parts of a 40% aqueous solution of potassium silicate (molar ratio 3.5), 20 parts of chromium oxide
3 parts of clay, 0.2 parts of sodium octyl sulfosuccinate, and 80 parts of water were placed in a pebble mill.
Dispersed to less than μ. This product was stored at 30℃ for 90 days.
After storage, 100 parts of this material was mixed with 100 parts of binder, and an inorganic composition obtained was sprayed onto a slate board to a film thickness of 40μ, and heated at 260°C.
It was heated for 15 minutes to harden it. Comparative example 3 30% aqueous solution of potassium silicate (molar ratio 3.5) 50
20 parts of titanium oxide, 0.3 parts of phosphoric acid, 5 parts of aluminum hydroxide, 5 parts of zinc oxide, and 20 parts of water were dispersed in a pebble mill to obtain an inorganic composition. This material was spray-coated onto a slate board to a film thickness of 40 μm, and heated at 260°C for 15 minutes to harden it. The test method was as follows. (1) Pot life Immediately after producing the inorganic composition, put 200 ml in a 250 ml polyethylene bottle, seal and store at 20℃.
The time required for the liquid to become non-liquid was investigated. (2) Appearance of coating film The smoothness and clutching of the cured coating film were observed with the naked eye. (3) Water resistance After being immersed in clean water at 20°C for 500 hours, the condition of the coating film was observed. (4) Boiling water resistance The state of the coating film was observed after being immersed in boiling tap water at 100°C for 3 hours. (5) Accelerated weather resistance Weatherometer (Sunshine Carbon)
It was used. The test conditions were in accordance with the JIS method. (Examination time is 500 hours) [Table]

Claims (1)

[Claims] 1 General formula M ₂ O.XSiO ₂ (where M is an alkali metal or N(CH ₂ OH) ₄ , N(C ₂ H ₄ OH) ₄ , N
(C ₂ H ₄ OH) ₃ , C(NH ₂ ) ₂ NH, where X is a positive number of 0.5 or more) and/or the water-soluble silicate is a calcium or magnesium metal fluoride. Or, 100 parts by weight of a modified product modified with an oxide of zirconium or vanadium metal, a hydroxide of an alkali metal of Group A of the periodic table or a calcium metal and/or an oxide of a calcium metal and a condensed phosphate and/or An inorganic coating composition characterized in that it contains 20 to 100 parts by weight of a reaction product with a phosphate.